Geometry Gym

In Progress: Louisiana State Museum and Sports Hall of Fame

2012-01-30T01:39:00.003Z

It's great to see details being published on projects that have been developed with assistance of Geometry Gym plugins for Grasshopper/Rhino.

ArchDaily has posted this article on the Louisiana State Museum and Sports Hall of Fame.

Method Design (in the design team with role as Geometry and Detailing Consultant) used the Geometry Gym plugin to exchange the Grasshopper geometric steel framing model into Autodesk Robot Structural Analysis where analysis and design checks could be conducted accurately by David Kufferman P.E. The model could then be exchanged beyond for coordination and fabrication. You can also find more details and other links by David Stasiuk on the Grasshopper website.

Revit IFC Plugin by Geometry Gym

2012-01-27T11:30:00.000Z

I've recently been advancing development on a tool/workflow that's really needed to use Grasshopper to somewhere near it's full potential for Architecture/Engineering. And that's to export the model into other BIM software with strengths and functionality that are not always evident or easily accessible in Rhino.

I started developing my IFC (neutral BIM format Industry Foundation Class) plugin (within Rhino/Grasshopper software) with the intent of enabling generation of BIM attributes and relationships to the already powerful geometric tool that is Rhino/Grasshopper, and then utilizing this in other BIM software without having to model everything again from scratch, and then maintaining/coordinating multiple models.

I touched a little about the current use of IFC as a model exchange in my technical paper last year. Presently to be IFC certified (and there is a current drive to improve on this) you effectively need to import/export IFC models for coordination. This can be done (with accuracy but certainly not efficiency) utilizing only two shape representations, linear extrusions and meshed/faceted breps.

This has led to a chicken/egg scenario, where BIM software vendors haven't imported advanced (and more efficient) shape representations (IFC is based on STEP model specification) because other vendors haven't exported them, and vice versa.

So whilst there is a long list of Software that interacts with IFC, it's really difficult (and I've discussed this with a number of big and small design firms in the past year or two) to use this "bridge" as it's intended.

Autodesk Revit is a very popular tool for Architects/Engineers to document and detail their projects. However testing of means to import models using neutral BIM formats (primarily IFC and SDNF) hasn't resulted in much to boast about and utilize. SDNF can generate native beam elements but can take hours (without succeeding) to import a pratical size roof model. The Autodesk IFC plugin import generates reference objects, useful for coordination, drawing and even schedules, but as soon as you wish to edit or manipulate the objects, you nearly need to model it again (as families aren't utilized and aspects such as analytical representations not created).

So, with a few Geometry Gym users looking for a work flow to get Grasshopper models into Revit, I've been looking for improved ways to do this using the Revit SDK. I started looking at direct model interaction, but for technical and practical reasons have decided a neutral bridge is the best way to do this. Most of my c# IFC code is reusable (with some interaction changes) as a Revit plugin (this is my first plugin outside of the Rhino/Grasshopper environment), and I've today posted an example import of a steel frame roof (British Museum Great Court Roof) using my own IFC engine.

There's lots of improvements and work to do, but I'm confident with time I can create a powerful IFC engine within Revit (as I've already achieved within Rhino/Grasshopper). The priorities for improvements are being driven by real project use of this tool (let me know if you have your own use for it) and will include curved members, orientations and synchronization options. If you look closely at the image you'll see Revit has still tried to be clever with the bevel/miter at element connections, hopefully I can find a way to disable this (as an option) as I believe its significantly part of a slow import process. Other objects including slabs, walls, MEP, etc etc will also be quickly added to the toolset.

It will be interesting to encounter the other hurdles and pitfalls in front of this development, but stay tuned to the blog for public release of this tool and examples of it's use. Feel free to get in touch to learn more (and influence it's development) in the interim.

Nurbs To Structural Analysis Profile

2011-11-30T17:59:00.000Z

At the request of the user, I've advanced the routines to convert arbitrary profiles (including nurbs perimeters) into the structural analysis section profiles capable of approximating this shape.

I've started with GSA, and will look into the other software equivalents shortly. In GSA the perimeter is defined as a polyline (I have enabled an input to define acceptable deviation from original curve), and properties such as area and inertia are computed from the polyline bounds.

The torsion property is not calculated, so I also enabled a section property modifier component to allow user specification of this value (as well as the others). There is a means to compute the torsional stiffness using soap film (which was the original reason I started coding mesh inflation), and I'll try to test this approach soon. If you have any papers or technical explanations/demonstrations of this technique, it can only help accelerate this if you can share it. Grasshopper definition can be accessed from here.

Tributary Areas and Variable Loading

2011-11-23T11:45:00.000Z

I've finally got some final improvements made to some useful functionality that can save hours of spreadsheet processing (or the like thereof).
I've enabled functionality within Grasshopper to compute tributary areas for nodes contained within a structural grid, as well as generating node loads from varying loading phenomena such as snow drifting or wind pressure.

This algorithm was used (in a more time consuming and specific way) for the 2012 velodrome roof in applying wind pressures from wind tunnel testing advice. At the time we were still optimizing cable spacing but still wishing to test multiple loading scenarios. This routine can work out tributary areas for arbitrary grids (based on mid distance from adjacent nodes), grid normals (although load can be applied in a uniform direction if desired) and utilize a varying loading intensity at different locations. This can be defined (or checked) intuitively from a surface (or polysurface) relative to a reference plane (the local z from datum defines the magnitude of loading pressure).

If you download the models below, you'll see it uses a reference plane from the structure (required for non-planar grids), and the relative position from the loading plane. I haven't yet developed grasshopper visualization of the generated node loads (it's on my todo list along with boundary conditions, releases etc) so you'll have to visualize in the analysis software. I also plan to implement face loading for finite elements in a similar manner, and any other suggestions that might arise from users, so don't hesitate to send them through.

Please check the results carefully, I hope you find it useful. I'm also very happy to assist in applying or testing this with your own applications to projects.
GSA model, SAP model (others to be added shortly).

Grasshopper Mesh to Finite Elements

2011-11-08T19:35:00.001Z

The ability to convert Mesh from Grasshopper (it could have been generated or imported into Rhino) into finite elements with ability to triangulate quad faces failing shape checks has been in the Geometry Gym plugin for some time. Recent requests from users recently enabled for the GSA plugin have included orthotropic material generation, nomination of finite element shape acceptance criteria (warning, severe warning, all) and ability to nominate varying orientation and property assignments throughout extent of mesh. Update from http://www.geometrygym.com/downloads and study this file for GSA, and this file for SAP.

SAP2000 Point Local Axis

2011-11-03T09:18:00.000Z

For the Geometry Gym plugin users, remember that I encourage and look forward to receiving suggestions and ideas for improvements and new features to the tools.

Here's a fairly simple one that where identification of node local axis can be straight forward in Grasshopper, but not so easy to do within the Structural Analysis software. This user wants to be able to apply a local coordinate system to the points (nodes) generated to SAP2000.

You can try for yourself here Download

IFC MEP and Reinforcement

2011-10-16T09:52:00.001+01:00

A quick post to highlight recent improvements to importing MEP and reinfocement data from IFC files, as well as Grasshopper Generation of these items. Still lots of improvements I'd like to make on this front, so please get in touch if you have particular requests.

Rhino/Grasshopper to Tekla

2011-10-11T07:44:00.003+01:00

In the past two months I have been progressing a Grasshopper plugin that enables direct exchange of data between Rhino/Grasshopper and Tekla. Tekla is a quite compehensive BIM application, although I have initially concentrated on the structures aspect for Fabrication.

This has been driven by a couple of projects where the steel work has been modelled in Rhino to fabrication detail and precision, either by python scripting or manual modelling. Rhino does not presently have direct extraction to NC format for fabrication, so a means to automatically extract this information from Tekla without duplicating modelling efforts has many benefits.

As part of this, I have been advancing some "reverse engineering" components to convert rhino polysurfaces (that do not contain "explicit history" information such as profile extrusion, end conditions such as miters or cut parts, or drilled hole locations. This can be implied from the features that the polysurface (brep) has.

I still find Grasshopper a very convenient means to assign attributes such as steel grade, finish, part/assembly numbering etc, so the Tekla plugin is only a GH addon at this moment. I am happy to assist with explaining/applying this tool to your project if it is of interest.

To download the installer, please visit http://www.geometrygym.com/downloads

As part of a presentation I will make later this week to the Light Weight Structures conference in Sydney, I prepared a grasshopper definition to emulate the primary structure of the velodrome (which owes a lot of it's success to the generative approach taken by all designers).

Here's another example model that you can try for yourself. Download

Mesh False Color

2011-09-06T06:48:00.002+01:00

A new component added to StructDrawRhino for generating mesh with false color from a list of values.

Grasshopper Example

IABSE-IASS Symposium 2011

2011-08-26T05:40:00.003+01:00

Taller, Stronger, Lighter

The 2011 IABSE-IASS Symposium is approaching very quickly now, and having received the program, I thought I would highlight a couple of recognized peers (real world and online) that might be of interest to followers of this blog.

Chris Wise, Expedition Director is presenting on the London 2012 Velodrome on Tuesday 20th at 3pm. This project (shortlisted for the Stirling Prize) was extensively modeled in Rhino using Geometry Gym plugins to exchange with Oasys GSA.

Michael Drobnik is presenting From Image to Parameter. Double Curved Canopy Muenchner Freiheit at 4pm.

Following soon after at 5pm is Gennaro Sennatore presenting Pumping vs. Iron Large Scale Adapative spatial Structures for whole-life energy savings.

Wednesday the 21st has John Harding presenting Structural Form Finding using Zero-Length Springs with Dynamic Mass at 10am

My paper Generative Models Utilized for Superior Design Development is scheduled for 12:15pm

Thursday the 22nd, Milos Dimcic is presenting Structural Optimization of Free-Form Grid Shells at 9:30am.

I was fortunate to work for Koroush Kayvani for 6 months on Wembley, and he is presenting Performance-based Design of Tall and Longspan Structures at 11:45am.

Expedition colleague and friend Fred Labbe is at 4:45pm with Evolutionary Design for "Environmental
Expressionism"

On Friday the 23rd Odysseas Georgiou will present Interactive Structural Analysis & Form finding at 10am.

Other presenters recognized from the Grasshopper forum that are presenting include Roel van de Straat, Clemens Preisinger and I'm sure I've overlooked others, please let me know if this is the case.

It should be a great opportunity to meet in person some online friends, and swap notes and learn from each other the application and use of these powerful digital tools.

If you, a friend or a colleague are attending, please don't be shy in coming forward to discuss. I look forward to the event and can't wait.

20th - 23rd September
Queen Elizabeth II Conference Centre
London

Generative Models improving Design Development

2011-07-18T16:46:00.003+01:00

I'm not sure how obvious the collaboration is between Geometry Gym and [UTO] to develop the Rhino/Grasshopper addons, but it's nice to see a co-authored article published in the Taiwan Architects magazine, Tawain Architects 2001/07

Credit for the example images to Benjamin Ennemoser and Phillipe Grotenroth (University Innsbruck, Austria exparch hochbau 2011)

Here's the article in English

As performative design concepts become more accessible to designers, we will see more analysis tools being developed for the design process. As we establish methods for understanding surface-based-analysis, we will be moving into volumetric-base-analysis.

Generative tools such as Grasshopper3d (Robert McNeel Associates) and Maya (Autodesk) are being utilized to explore architectural projects and inform design decisions with increasing popularity. However, rapidly produced multitudes of options will not be utilized to full potential if entire design team assessments take days or weeks to fulfil. To maximise the potential of these tools, teams must efficiently assess multiple objectives and criteria, to seek optimal solutions. Utilizing the generative information model as input to analysis and simulation tools (including structure, services, environmental, construction programming and cost assessments) can facilitate superior design decisions.

This article outlines and demonstrates software developments enhancing Grasshopper3d as a generative design tool for the architecture and construction industry. Additional functionality enables designers to assign attributes of design elements that can be utilized in exporting the information model for wider design consideration. Present industry practises where multiple models are independently created require consuming efforts in updating and coordinating. Duplicated, abortive and redundant design efforts are rife, and given the time consuming nature of these tasks, the potential to improve and assist these procedures is enormous. There is scope for substantial improvements for this process in the earliest phases of design, when identifying the strongest concepts can have the greatest impact on the final product and the least constraint is experienced to change.

Structural Analysis

Generative modeling for developing structural analysis models has been prevalent for years, primarily in the form of authoring spreadsheets. Geometrical description using imports such as DXF or DWG cad models have also been used extensively, although this process typically requires manual application of analysis attributes not supported such as constraints, materials and loads.

Evaluation of performance relating to alternate design scenarios is accelerated by producing in bulk the structural analysis attributes as related to the generative model.

This is shown for the 3-dimensional proximity truss structure as a Structural Analysis with Geometry Gym plugin for Grasshopper and Oasys GSA

Building Energy Analysis

Ecotect is a highly visual software for architects to work with environmental performance issues. It is designed for early stages of conceptual design, and encourages play to understand environmental factors and interactions. Ecotect works on the principle of “progressive data input”, that means that it is prepared to give visual feedback even with very little information. Not all aspects of a scenario have to be spelled out in detail.

In fact the simulation can be done earlier, and as the model is refined, results become more accurate.

GECO is a Grasshopper plug-in developed by [UTO] that offers a direct link between Rhino/Grasshopper models and Ecotect. The Plug-in allows you to export complex geometries very quickly , evaluate the design in Ecotect and access the performances data, to import the results as feedback to Grasshopper. This could be done as single process or loop to improve performance and the design of a building in the context of its environment.

The single results of the process could be saved inside Rhino in the vertices of the analysis mesh to store data for later use inside different design approaches.

BIM Advancements for Rhino/Grasshopper

2011-06-30T14:35:00.001+01:00

RhinoForYou presented Geometry Gym BIM enhancements for Rhino3d / Grasshopper3d at the BIM Day event in Paris earlier this week.

It was a good opportunity to enhance and improve the IFC plugin testing IFC files generated with other software. Improvements have been made for file processing times (with more to come, but better for all IFC authoring software to produce higher quality files).

This clip shows importing of the Tekla House model authored in Archicad, and an associated MEP file. It demonstrates the new IFC tree data viewer in Rhino.

The second clip is a model prepared by VisualARQ, the IFC data was optimized using Geometry Gym tools to reduce the file size by a factor of 10 (permitting more acceptable access time for Rhino/Grasshopper). The file is then imported and edited in Grasshopper, first deleting some members and then generating a new parametric set.

This plugin is undergoing continual improvement, if you have requests or requirements that you would like included, please get in touch to discuss them with me.

Grasshopper Catalogue Profiles

2011-06-19T15:26:00.001+01:00

I've just added a new feature to StructDrawRhino addon for Grasshopper that allows easier nomination of catalogue profiles (before you had to use a string). If I haven't already included a catalogue profile or range that you would like to use, please get in touch and I'll add it ASAP. http://www.geometrygym.com/downloads

Grasshopper GSA Form Finding Examples

2011-06-06T13:56:00.002+01:00

I sat in on the recent Oasys GSA webinar on form finding conducted by Pete Debney, for those that missed it, don't despair. A recording of it, as well as the presentation and example models can be found here:

http://www.oasys-software.com/support/events/webinars/form_finding_with_gsa.shtml

I think it's a great resource and introduction/explanation of some of the form finding options provided by the Oasys GSRelax solver.

I also think each of the 3 example models are well suited to a parametric exploration using Grasshopper (using the Geoemetry Gym plugin to exchange the model data with GSA), and I'm posting these definitions here so you can try for yourself.

The gsa relax solver is not included in the standard evaluation license, but you can email them and ask for access to it. I'm still enhancing the plugin in a few areas, you might see toolbars wander if you run GSA as a background service (ie if you don't have GSA running when you open the grasshopper definition, the plugin will start it in the background for you). If you do have GSA open and Grasshopper appears to "freeze", activate GSA and close any confirmation dialogs that might appear.

Generating the model with geometric shapes using StructDrawRhino will be enhanced shortly, as well as any user requests so send them through. Make sure you have latest GSA and StructDrawRhino plugins from here: http://www.geometrygym.com/downloads and the definitions are derived on the basis of a rhino document being open with metre units.

Force Density form finding of a cablenet bridge. Grasshopper Definition

Compression Shell form finding using Analysis properties. Grasshopper Definition

Soap Film form finding of tensile membrane with back stay Grasshopper Definition

Rhino v5 Extrusions, GeomGym Plugins

2011-06-03T10:33:00.002+01:00

I've been enabling Rhino version 5 light weight extrusions to the Geometry Gym Rhino plugins, that uses less memory, meshes faster and saves out to much smaller file sizes.
http://wiki.mcneel.com/rhino/rhinov5status_extrusions

I've seen and heard some positive demonstrations and reports of this improvement, but decided to do some quick bench marking for myself and the results are impressive.

I prepared some approximate models of the British Museum Great Court Roof as part of this discussion with importing IFC models into Archicad.

The model comprises 5180 members, and the improvements from v4 to v5 are really impressive.
I've benchmarked using the Geometry Gym IFC importing plugin, which will use the new extrusions when running in v5. If you want to try for yourself, install/update the plugin, http://www.geometrygym.com/downloads and the IFC data file can be downloaded here.

Or, if you just want to open the rhino model, download here.

Time wise (only considering the generation of the extrusions, ignoring file reading time etc) it took 35 seconds on my computer to generate 5180 version 4 extrusions. In version 5, it took less than a second.

When saving out the rhino model, version 4 produced a file 74 MB, version 5 produced a 3 MB file.

And there is very little lag or delay when panning, zooming and rotating the v5 model, in comparison with v4.

The only drawback (which should be a temporary matter and improved as the beta version of 5 progresses) is a much slower start up time for version 5, particularly 64 bit (which seems to be made slower by loading geometry gym plugins which is being investigated).

However, if you're working on skeletal or frame models, I strongly recommend taking the step up and using v5. Extrusion elements also can accomodate end miter planes, which I'm in progress of enabling to the plugins.

With regards to the IFC plugin, you might also notice some other speed improvements when importing large faceted brep models generated by other BIM software.

Feel free to comment with any suggestions or observations of your own.

Grasshopper - Solver Results

2011-05-03T08:43:00.003+01:00

I've been progressing components for accessing Structural Analysis solver results recently, primarily for Oasys Gsa and others will shortly follow. I'm also in early phases of testing a structural analysis solver directly within a Grasshopper plugin (to analyze linear static frames directly and extract results, which should be quicker than sending data to external programs).

I've enabled a Grasshopper component for my vector field to streamlines algorithm, also the work of SPM is looking encouraging in this area.

If you don't have Oasys GSA, you can try this definition (I've baked some principal stress lines into the Rhino document) or you can test the result extraction from GSA using this definition. Both need this Rhino document with basis mesh.

Also, here's a definition demonstrating generation of false color mesh for Von Mises Stress.

I've also enabled some new features for form finding directly from within Grasshopper using the GSA fablon solver, here's a nice example from a user request outlined here. Grasshopper Definition

I look forward to hearing suggestions and questions from users.

GH GSA Form Finding Tensegrity

2011-03-31T00:51:00.004+01:00

A first study of tensegrity form finding using GSA, I plan to add to this post some models of some nice towers.

Here's a start to that, note I'm looking to adjust the component calculation order as the solver needs to be computed only after all other components have calculated. If you have problems of only partial model update, try deleting and adding a new solver component (or disabling, recomputing, and enabling).

Model Files to try yourself.

Galapagos and GSA solver

2011-03-23T11:33:00.005Z

It's still early stages of testing and development of some recent work I've been doing to enable access to GSA solver directly within Grasshopper (and importantly Galapagas).

The attached example is still primitive, I'll find a moment to extend it to include a stiffness per mass objective, but it does demonstrate a few aspects of using this technique.

All feedback appreciated, including requests for more components to save manual generation of GWA attributes (which is shown for the point load generation).

Grasshopper Definitions
GSA SAP SpaceGASS Egret Robot

Grasshopper-GSA Form Finding and Structural Analysis

2011-03-21T06:15:00.004Z

Some really exciting new features to be activated in the next public build of the Rhino/Grasshopper plugin connecting to Oasys GSA that will allow generation of a complete Structural Analysis model within Grasshopper including loads, materials, analysis tasks and solver controls. This will allow form finding of membrane and tensegrity structures incorporating advanced structural attributes including loads, with realistic materials.

This will not be real time "dynamic" response such as kangaroo physics plugin (which at present can not perform at real time speeds with realistic materials and stiffness).

Interrogating and utilizing analysis results will also be enabled, including more conventional models and frames.

If you have requests/suggestions for this release don't hesitate to get in touch. Other popular solvers including SAP2000, Robot and Strand7 are expected to follow in the near future.

I'll shortly be posting more detailed instructions, but for the time being you can download the grasshopper definition from here : Grasshopper Definition You'll need latest Plugin for GSA from http://www.geometrygym.com/downloads

GH to GSA Finite Elements from Area and Regions

2011-02-22T05:01:00.001Z

A feature that I added earlier this year was the ability to generate Structural Areas and Regions for Oasys GSA from Grasshopper. You then mesh the structural areas within GSA.

Here's the associated models to try yourself.

Rhino model Grasshopper Definition

SCIA and Grasshopper

2011-02-20T06:41:00.002Z

Thanks to the Scia Open Interface (which is a library for reading and writing XML data files for Scia) I'm pleased to present a new plugin for exchanging data with Nemetschek Scia. Thanks in particular to Mark Flamer and Peter Zalman for their assistance with this.

Here's two example files to start with, the popular 3 pin truss generation

Rhino Model Grasshopper Model Scia XML Export
and generating a mesh model:

Rhino Model Grasshopper Model Scia XML Export

The Scia open interface is still work in progress, it's not allowing me to open models yet and I see node restraints are generated in xml but do not seem to be acknowledged by scia in the latest version. So please use with care. But if you would like to see these improvements and more in the tools, the more interest I can demonstrate I'm sure will encourage fixes and support for this development.

Installation instructions are here: http://www.grasshopper3d.com/group/geometrygym/forum/topics/installing-geometry-gym I'd recommend installing StructDrawRhino as it is also used in some sample models.

IFC Generating Quantity Measurements

2011-02-04T06:26:00.001Z

I've just returned from two weeks of visiting various architecture and engineering firms in Paris and London, and one of the latest features that generated lots of interest is the new developments to generate quantity and
planning information within Grasshopper and Rhino3d.

Not only can you have real time response of these quantities, but also export these downstream to your other BIM software for use in schedules, reports etc etc. I have set it up so the property sets and element quantities are fully customizable, so that you can ensure the attributes are tagged as your BIM software will recognize it (In the attached example, I've based this on a Revit sample file provided to me).

There's a lot more that I can enable with this including building services, costing, building performance etc etc, so if you have ideas or requests, please send them through.

Please test this out for yourself on this sample tower model, you'll need the latest IFC plugin. Installation instructions: http://www.grasshopper3d.com/group/geometrygym/forum/topics/installing-geometry-gym

Grasshopper Model
IFC Model Data

IFC Shape Representations

2010-12-31T06:56:00.001Z

In response to the discussion on IFC Shape Representations on the IFC Linkedin group I decided to implement some further shape representations as examples and to find out other software reading and exporting models utilizing them. From previous posts and comments, it seems like SCIA engineer might not have too many companions in recognizing and utilizing shapes other than the standard extrusions and faceted breps (which are often approximations). I'm sure there might be some slight amendments I might make to the tags of the representations (I've implemented them as best I can interpret the informal propositions) but it's difficult to clarify them as examples of these files seem scarce.

Feel free to try and import these models into your BIM software (including viewers), and either comment or email me and we can tally which shape representations can be used with other software.

A bounded plane surface : Grasshopper Model IFC Export

A revolved area solid : Grasshopper Model IFC Export

A section spine solid : Grasshopper Model IFC Export

Note that IFC does not explicitly define the surface geometry between the section spine profiles, I've used Rhino loft for the time being.

A swept solid : Grasshopper Model IFC Export

(I need to implement IFC curve parameterizations for more curves so this component is hidden for the time being)

BIM: Importing IFC to Grasshopper

2010-12-15T13:41:00.000Z

New features added to Geometry Gym IFC plugin for Grasshopper and Rhino. You can now import existing IFC data files into Grasshopper (more improvements on visualization coming soon). There's also specific components for tagging objects as slabs, walls, stairs, beams etc. Download from http://www.geometrygym.com/downloads

Example definition for importing IFC data: ReadIFC.gh

Sample IFC data file : testTower.ifc

Priority will be given to new features requested by users, please keep sending them through.

Fantastic projects utilizing Geometry Gym

2010-12-11T14:49:00.001Z

Obtaining permission from commercial users (and their clients) is difficult, but it's nice to see some fantastic work published from the University of Innsbruck. Congratulations to [UTO] and the designers researching and studying there.

Thomas Buseck has recently posted details of his projects at http://thomasbuseck.blogspot.com/ Very impressive and I look forward to seeing more of your work.

Benjamin Ennemoser has also been combing the various Rhino/Grasshopper plugins to develop the form for his thesis project, details at his blog http://ennben.blogspot.com/

It's always great to see the project work assisted by the Geometry Gym tools (thanks to all those who email me images and details), and if you'd like to also see your work raised here, please let me know.

Grasshopper IFC generation New Features

2010-11-29T10:20:00.001Z

New features for extruding and remapping (arraying) building information models (BIM) in Grasshopper, exporting using IFC.

Grasshopper Definition

IFC Export

YouTube demonstration uploaded shortly.

Grasshopper generating IFC Update

2010-11-15T06:16:00.004Z

Thanks to Scott Davidson for the gothic inspiration and a great example of Grasshopper Generation and the ensuing improvements for exporting from Rhino/Grasshopper to IFC (can be imported by BIM software such as Revit, Archicad, Digital Project, Microstation, Tekla etc etc).

IFC2x4 is anticipated for formal release next year, which includes NURBS representations and should enable Rhino/Grasshopper models to be exported with greater accuracy and with greater ease. Until then, IFC2x3 does provide means and ways to represent shapes and forms created by nurbs, and this blog post will demonstrate some of them. Note most software does not recognize or work with all aspects of IFC, so approximations such as the first for faceting the brep may be your only option.

The first shape representation is using a faceted brep, effectively meshing the surface. Unless your original shape is a faceted brep (with planar faces and straight edges), there will be a loss of detail, but you can control the refinement of the meshing process (introducing more faceted faces).

Grasshopper Definition Generated IFC Data

Theoretically it's not necessary to approximate the form with a faceted brep if you can generate it using processes and shape representations within the IFC specification. This includes extrusion and boolean operations which can be used to form this vault. In practice, it seems very few BIM software and IFC viewers acknowledge or are capable of these operations, so you may be forced to use the faceting approximation. Please test these models with your favorite IFC software and feel free to post your observations as comments.

Most programs comply with extrusion, here's Archicad importing this model:

Grasshopper Definition Generated IFC Data

I've struggled to find even an IFC viewer to successfully display this model, but there's no warnings of non-compliance. The boolean operations should work with a rhino model absolute tolerance set to 0.01

Grasshopper Definition Generated IFC Data

Please post any comments with software you can or can't open these models with. If you've any particular shapes you'd like to export that aren't successful, please get in touch and I can help advise.

Instructions for getting started with the IFC plugins are found here.

Grasshopper generating IFC

2010-11-08T10:49:00.001Z

Here's the first demonstration and example files for generating IFC from Grasshopper using the Geometry Gym plugin. This is just the beginning. IFC can be read by popular software such as ArchiCAD, Digital Project, Revit, Tekla etc etc. Download the plugin from http://www.geometrygym.com/downloads

Please try for yourself, and report all ideas, suggestions and problems.

Here's the Rhino file for the tower massing: Rhino Model
Here's the Grasshopper definition: Grasshopper Definition

Autodesk Robot Geometry from Grasshopper

2010-10-25T07:53:00.004+01:00

More explanations and descriptions coming soon. I'm in the process of developing creation of Robot Geometrical objects within the parametric Grasshopper environment. Presently this includes polyline base revolutions panels and cladding panels. I expect further development of aspects such as poly curves (with arcs) and extrusions to be added. Please report any suggestions, observations and ideas and they will implemented with priority.

Polyline Revolution

Rhino model
Grasshopper Definition

Cladding Panels

Rhino model

Grasshopper Definition

Update to Rhino/Grasshopper plugin to SAP2000

2010-10-15T08:49:00.001+01:00

The Rhino/Grasshopper plug-in generating and exchanging data with SAP2000 has been upgraded and now includes the option to "bake" the data directly from Grasshopper to SAP using the OAPI COM interface. No longer needed to save and import a text data file.

If you rebake variations, you might observe historic nodes being left in the model, I am still awaiting advice from CSI on an issue with deleting unattached points. There's more improvements that will quickly be implemented, if you've ideas or suggestions, please send them through.

You can download the 3 pin truss models : Rhino and Grasshoper
The basic mesh and restraint model: Grasshopper

Network Patch

2010-09-17T13:18:00.001+01:00

A stunning example of checkerboard patch, the Pavillion Serpentine Gallery (Photo by Sylvain Deleu ) prompted David Lister to ask how to achieve this in Grasshopper. The algorithm is a variation to the curve network filleting routines in StructDrawRhino, so I've just uploaded a new build with it included.

Rhino Model available from here.

Grasshopper definition available from here.

Tessellation - Approximating a Form

2010-09-08T07:24:00.001+01:00

An example of using the recent addition of Tessellation to the StructDrawRhino Grasshopper plug-in to define a shape or form. Mario Vergara recently posted to the Grasshopper forum about using L-systems to generate a shape or form. Whilst the attached example doesn't utilize this, there is no reason why the base form could not be generated in a plug-in like Rabbit and then used as input to the SDR tessellation. Improvements on the agenda include curve definitions for the intersection path. Please send through other ideas and suggestions. Be patient with the algorithm, it should run faster in Rhino v5.

You can download the Grasshopper / Rhino file from here.

Grasshopper Curve Force Density (Great Court Roof Revisited)

2010-09-01T17:02:00.001+01:00

First thing to state, I plan to revisit the topology (connectivity) of the curve network to get a better result, so please come back soon and check if it's updated.

I've been adding curve network force density tools into the Grasshopper StructDrawRhino plug-in. There's progress on using the Great Court Roof as an example.

You can download the Rhino file here and the Grasshopper definition here.

Also possibly of interest is a "reverse" force density where it iterates through the network nodes and repels the neighbouring nodes rather that move the current node, which can be used in some circumstances to produce equal length curves. Here's one example, although it seems there's lots of scenarios where it's not so successful. I've put a slider on the iteration so you can see it converge on an answer, and it's producing two adjacent loop results so you can compare.

Rhino file here and Grasshopper file here.

Digital Design Workshop Johannesburg

2010-09-01T10:45:00.000+01:00

A fantastic event held last month, arranged by Hugh Fraser and supported by PG Group, it was a fantastic opportunity to meet South African Architects and Designers keen to learn more about Grasshopper3d and Digital Design and Fabrication. Kristof Crolla and Jeroen van Ameijde led the workshop, I provided additional advice and assistance with technical aspects and Grasshopper modelling.

It's worth watching this entertaining summary by Hugh which is the next best thing to having been there:

Leon Krige (who exhibits a lot of his fantastic photos, check out http://www.fluide.co.za ) took a few of the photos shown below.

We were all disappointed the glass could not be cut in time, but still some great results were achieved and we all learnt a lot. The format of splitting into small groups, building prototypes of ideas and stage design competitions to reduce down to three final projects was a great format.

If you get down to Main Street quickly enough, you can still find the mdf sculpture in the sewer drain (but rain will be here soon) and possibly the other projects in Main Street Life.

Some of the work shop participants in Main Street Life foyer under one of our final three projects.

Leon has managed to make the sewer look relatively attractive, but it's hard to convey the smell on the internet.

The third of the projects which is yet to be realized in real life.

Hopefully this is the first of a many of these types of events. If you're interested, please don't hesitate to get in touch.

Tessellation in Grasshopper (Beijing Watercube revisited)

2010-08-20T11:55:00.000+01:00

I've started enabling the tessellation (polygon packing) routines in Grasshopper, and the Bejing Watercube is such a great example of using this geometry I thought I'd post the grasshopper version.

Rhino file from here.

Grasshopper definition here.

I've also started implementing some spline variable cell filleting, I'm still looking at options for generating best results. An improvement on constant radius results.

Rhino file

Grasshopper definition

Three pin Truss

2010-08-05T06:11:00.002+01:00

An assignment was set recently at UC Berkeley to model a three pin truss utilized at the previous Eurostar Terminal at Waterloo, London.

A question on how to generate this arrangement was posted on the Grasshopper forum, and I think it is a fantastic example of structure that should be modelled in Grasshopper to achieve the best design possible.

The assignment due date has passed (I hope), so I think it's safe to post how I would use the Geometry Gym plug-ins to model this structure. This includes a new StructDrawRhino Truss component, that allows you to select the nature of the truss connectivity (at present, Pratt, Warren, Vierendeel and Brown) between two chord curves. Other truss types are available upon request.

GSA screen Capture

Download AVI from here

Robot screen Capture

Download AVI from here

And the files so you can try for yourself:

Rhino Model (Required for all Grasshopper Definitions)

Grasshopper definition for StructDrawRhino
Grasshopper definition for Oasys GSA
Grasshopper definition for Autodesk Robot
Grasshopper definition for SAP
Grasshopper definition for SDNF (Steel detailing neutral format can be exchanged to BIM software such as Tekla and Digital Project)
Grasshopper definition for Strand7/Straus7
Grasshopper definition for Sofistik

Other software models coming soon, please request to accelerate.

Skulpture

2010-08-02T17:20:00.002+01:00

Wieland Schmidt recently posted two stunning renders of sculpture produced utlizing Geometry Gym StructDrawRhino routines in Grasshopper3d. The components for geodesic domes, cell filleting and mesh inflation were used. Fantastic work Wieland, thanks for sharing and would be nice to see them created in the real world.

Generate Finite Element model in Rhino and exporting back Stress Results

2010-07-29T13:01:00.003+01:00

I've had a number of requests lately about analyzing Rhino/Grasshopper mesh and using the mesh results back in Rhino/Grasshopper. Thanks to Tom of [UTO] for this particular example, which was mesh created in Grasshopper using WeaverBird.

The video above demonstrates this using GSA (which is free for Students).
The rhinocommand ssiGSAMeshtoGWA translates a Rhino mesh into GWA data which can be pasted in the gateway. The mesh remains unchanged, although the routine will triangulate quad faces that are not within GSA planar tolerance.

Node Restraints, finite element properties and loads are quickly applied in GSA, and the model analayzed for results. The results can be exported to a text file, which can then be loaded back into Rhino. The number and nature of these results can be controlled in the GSA export process, and this can be saved into the GSA model as saved output to be recalled later. ssiGSALoadResults command can be used to open this results file and false-colour the mesh. Note the model data must be active in either the Rhino (or Grasshopper) plug-in (thus I imported the model data back).

There's improvements to be implemented in the near future, including other results and importing into a Grasshopper component.

Here's the files so you can try for yourself:
Rhino Mesh Model
GSA Model

19th August 2010
Some further discussions and experiments with finding vector fields on the Grasshopper forum for the model have prompted me to append this blog post.

I've added some additional functionality to ssiRhinoGSA (v0.8.0037 and newer) to allow using the command ssiGSALoadResults command to interpret Principal stress data results. An export such as this results.txt
can be read, I used a scale factor of 2e-8 and unsigned magnitude to generate the lines representing the principal stress vector field. You can then set these lines in Grasshopper and convert to vectors as shown in this Grasshopper model.

Sofistik CableNet from Grasshopper

2010-07-20T14:43:00.001+01:00

Progress of Sofistik model generation from Grasshopper3d. You can now nominate lowest acceptable beam and node generation, apply beam properties such as releases, offsets as well as node restraints. Lots more coming

youTube screen capture or download better quality AVI from here

Grasshopper definition

Rhino Model

Grasshopper3d to Autodesk Robot - CableNet

2010-07-06T15:23:00.003+01:00

Progress on the Geometry Gym Rhino3d/Grasshopper3d to generate and exchange Autodesk Robot data is going well, above is a screen capture demonstrating parametric exploration of a cablenet roof (I've used beam profiles so they can be seen in the video).

You can realize great benefits to determining an efficient cable scheme by parametrically exploring the spacing, depth and easily measuring quantity, cable end fittings etc.

In a near release the node restraint generation in Grasshopper will also be added to the Robot Model, and on the agenda in the short term is to add ability to generate loads, hinges and lists within the Grasshopper definition.

To try yourself, download the plug-in from http://www.geometrygym.com/downloads
The Rhino model with saved profile/view can be downloaded here: Rhino Model
And the Grasshopper definitions : (Other programs coming shortly)
ROBOT
GSA

Exporting Grasshopper to Digital Project/Tekla/BIM

2010-07-03T14:22:00.002+01:00

Recently I've been concentrating on development of neutral BIM file formats, with the primary goal of enabling parametric modelling of structure in Grasshopper and then exporting those models into other modelling software such as Digital Project, Tekla, BIM software and other design software.

One of the biggest frustrations I've experienced, and a large reason why I've undertaken an opportunity to develop Rhino Plug-ins is to reduce duplicated modelling work and the associated time and cost in coordinating models. On a given project, each of the design consultants (ie architects, structural engineers, services engineers, contractors and project managers etc etc) will build digital models of the project to analyze, review and communicate their work. Even within the same office, there might be multiple models created (and more importantly maintained and altered as the project changes). The ambition and philosohy of BIM is ideal to improve efficiency and productivity, but I'm not expecting this to be a new idea to anyone reading this post.

So, to parametrically generate BIM information from parametric modelling software such as Grasshopper is an amazingly powerful tool and workflow. Already available for use and testing of this workflow is the Geometry Gym SDNF plug-in (available from http://www.geometrygym.com/downloads ), which is capable of skeletal or steel frame model exchange. I've attached an example geodesic dome model for interested users to test and try this work flow. Soon to follow will be IFC (Industry Foundation Class) attribute generation which will allow further information such as walls, slabs, doors, windows etc, and hopefully it goes a long way further than that.

Make sure you also download the StructDrawRhino plug-in for the Geodesic component, and you will need the free trial license to activate these Grasshopper components (follow the prompts).

Here's the Grasshopper definition and Rhino model with the SDNF property table saved in it: Rhino Model Grasshopper Definition
You can vary the inputs of the geodesic dome if you wish, and you can parametrically modify the beam profile using the property table accessible from the second button on the SDNF toolbar (use the spanner button to update the profile with that selected in the pull down menus). When happy, bake the Steel Beams into the Rhino document to activate them (they are virtual whilst in preview mode) in the SDNF database. If you alter the grasshopper definition and re-bake, the plug-in will try to detect the previous baked elements and delete/replace them.

If you click on the Export SDNF button, you are prompted to generate SDNF ver2 file (I believe Digital Project uses this format) or SDNF ver3 by default. Then try importing the files into SDNF accepting software.

Note, there are issues to do with different software librarys labelling profiles with different formats, and you can try altering the catalogue definition. It's possible a means of a mapping table facility may need to be provided in the near future. If you can give feedback on what does work and what doesn't, I'm most grateful.

Some more examples coming soon, Here's my exports if you wish to try the generated files without the plug-in:

SDNF ver 2 SDNF ver 3

ssiRhinoIFC Progress - Industry Foundation Class 2x3 - Import and Export

2010-06-27T22:41:00.005+01:00

The first public alpha for ssiRhinoIFC is available for downloading at http://www.geometrygym.com/downloads This allows importing, and some introductory exporting of IFC (Industry Foundation Class) version 2x3 for buildings and structure.

Whilst I'm the first to acknowledge there's a lot of work to be done to cover this comprehensive neutral BIM format, the basis of a very useful tool is already evident. Working in a consultancy design office, we were often sent primitive DXF/DWG mesh models from steel detailers using software such as Tekla. More intelligent models such as IFC will provide greater advantages for coordination and checking.

And IFC should also provide a very useful means of import/export to programs such as REVIT. An automated workflow from Grasshopper generation to external BIM software will reduce replicating work and coordination.

Development priority will be given to problems, suggestions, observations and ideas raised by users, so please download the plug-in, get the trial license and start exchanging IFC data with your other programs.

Start your testing by importing some of the example models I've been using, http://bimwiki.com/@api/deki/files/79/=NIST_IFC_Sample.zip and http://bimwiki.com/@api/deki/files/80/=Sample_IFC_files.zip contain a few model files to test.

And see if the IFC file exported from this Rhino model is compatible with IFC viewers and modifying software you use. You need StructDrawRhino installed, use the command ssiIFCExport and select the beam centrelines. You can move the locaction of the curves, apply different properties in the SDR property table etc.

A lot more to come on this in the near future, stay tuned....

David Rutten & Friends (AA London Lecture)

2010-06-04T08:34:00.004+01:00

In front of a packed house, David Rutten, Daniel Piker and myself presented our recent work and developments for generative modelling utilizing Grasshopper3d.

You can view the presentation online at http://www.aaschool.ac.uk/VIDEO/lecture.php?ID=1212

David presented on his latest feature of Grasshopper, Galapagos (a genetic algorithm based solver). It's fantastic how David can provide such an amazing user interface to the powerful tools he programs (When I was assisting Fred with the Genetic Algorithm solver for Naples, we had no time to program this visual feedback).

Daniel's work with Physics expressed in Kangaroo is amazing, and very popular. It's going to be very exciting to see how designers utilize this into their design process.

And I presented on the Geometry Gym plug-ins featuring computation geometric design, and the existing and soon to be released BIM aspects of my tools. It is becoming more and more apparent that if we have the power to generate many options rapidly, we need to ensure our evaluation tools (Such as structural analysis and other consultant design software) needs to be able to generated and evaluated quickly. And there are massive benefits to minimizing coordination and duplicated model generation if we can transfer a Grasshopper model into BIM programs such as Tekla or REVIT (amongst many). The Geometry Gym SDNF, IFC (Industry Foundation Class) and CIS/2 tools are progressing rapidly.

Mesh Inflation in Grasshopper (ETFE)

2010-05-16T15:05:00.002+01:00

Here's the first effort at a solver to inflate meshes (controlled by pressure) in Grasshopper.

More examples and improvements to come (note the double sided pillow is not enabled yet).

Grasshopper definition : inflateMesh

And a second definition to demonstrate applying restraints and inflating solids or polysurfaces:

Grasshopper definition: boxInflation

2010 SEI Student Structural Design Competition

2010-05-02T15:42:00.002+01:00

Congratulations to Ben Sitler on being awarded 2nd place in the 2010 SEI Student Structural Design Competition.

Ben entered the competition on his own, against teams from around the US. He found the efficient work flow gained from using the Geometry Gym Rhino plug-ins gave him an advantage against teams.

Ben has been kind enough to permit me to show his Gridshell design for Jadwin Hall. These images are taken from his Thesis, Sitler, Ben. “Integrated Digital Design to Construction Workflow: from a structural engineer’s perspective.” Thesis, Princeton University, Princeton, NJ, 2010. Print.

Grasshopper Gallery

2010-04-19T13:26:00.003+01:00

I thought I'd post some images of some great work being posted on the Grasshopper NING.
Unfortunately most commercial projects are kept in house, but it's nice to see these results in the public domain.

Primarily StructDrawRhino has been used in Grasshopper, in partnership with other plug-ins for some. If you'd like to have your own work displayed, let me know and I'll add it in.

Wieland Schmidt

Mark James

Chris E (work in progress)

Ivan Kiryakov (Refer blog post Going Green or Ivan's Gallery)

More to come....

Simply Rhino & AA Grasshopper Presentation Event

2010-04-16T16:03:00.000+01:00

Simply Rhino & Architectural Association Grasshopper Presentation Event

David Rutten & Friends
to present Grasshopper
at Architectural Association London

12th May 2010 from 1pm to 3pm

Details here: http://www.simplyrhino.co.uk/about/AA.html

Parametric Structure Models in Grasshopper

2010-04-16T08:46:00.008+01:00

The first SSI plug-in for Grasshopper with Structural model Interaction has just been uploaded.
http:\\www.geometrygym.com/downloads Versions for GSA, Strand7/Straus7 and Sofistik are available, other modelling interaction will soon follow (ie SAP, SDNF, Robot etc). If you want to influence the priority list for release, send me an email with which version you'd like to use.

So, here's a screen capture demonstrating the use of the plug-in, and sending the parametric model out of Rhino into GSA (similar for Strand7, Sofistik and others).

And to try this for yourself, here's the sample models shown and a revisit of the Gherkin.

First Grasshopper Definition to generate structural beams : GSA Robot SAP2000 Sofistik Strand7

A simplified version of Newcastle Millenium bridge. I haven't had a chance to add a slider to rotate it yet :-(

Associated Rhino model with properties : GatesHead Rhino Model
Grasshoppper Definition : GSA Robot SAP2000 Sofistik Strand7

Revisiting the mini-Gherkin. Note I'm sure if I get a chance to study Grasshopper Trees and Branches this definition could be simplified a bit.

Associated Rhino model with properties : Gherkin Rhino Model

Grasshoppper Definition : GSA Robot SAP2000 Sofistik Strand7

Some Green

2010-04-10T22:17:00.001+01:00

Ivan Kiryakov has produced some really stunning work with Grasshopper, and it's nice to see him using StructDrawRhino to produce some of these forms and shapes. I'm referencing some of the photos into this blog entry, but you should check out his album at http://www.grasshopper3d.com/photo/album/show?id=2985220:Album:56274

Genetic Algorithm - Naples Metro Station

2010-04-10T22:03:00.002+01:00

http://www.bdonline.co.uk/story.asp?sectioncode=453&storycode=3161354&channel=783&c=2#ixzz0khJ86uns
BdOnline has published an article on a project I was involved with assisting Fred Labbe at Expedition.

The computing power required to calculate the generations of solutions was significant, and the project always attracts debate and interest when presented/discussed with other designers.

You can find a pdf of Fred's presentation in the project info at the right hand of the project page at http://www.expedition.uk.com/index.php?pid=141

Force Density Relaxing Roofs

2010-03-25T08:55:00.006Z

Arthur Mamou-Mani posted on the Grasshopper forum (http://www.grasshopper3d.com/forum/topics/tensile-membrane?commentId=2985220:Comment:54158 ) about tensile membranes and Rhino plug-ins that can compute shapes and forms.

I thought the problem looked interesting, and thought I'd see what I could achieve with the new mesh minimal surface tools I've been improving in StructDrawRhino.

You need the latest version of StructDrawRhino (http://www.geometrygym.com/downloads ) and a license file, but you can try this for yourself.
Note, if you altering the inputs such as the control curves, I'd recommend disabling the Grasshopper meshing component temporarily, and then reconnecting it when you want to recompute.

Rhino Model
Grasshopper Definition

What you find in the basic definition, is that the isolated mesh restraint points produce a very pointed roof, in reality we wish to strength the links along the ridge line.

Here's a revised definition that produces a more desireable result
Strengthened Ridge Line Grasshopper Definition

Note that the image shows the mesh baked, which helps identify the isocurves or underlying mesh. Toggling the preview update input can give some insight into how the algorithm is working, at the expense of a slower result.

Costa Minimal Surface

2010-03-21T11:20:00.009Z

Force Density (Using the Mesh Vertex Repel command)

Grasshopper Definition

This definition calls on the ggForceDensity Relax functionality to compute a minimal surface discovered by Costa. This command doesn't compute minimal surfaces for all mesh, but at least seems to give a reasonable impression for Costa Minimal Surface.

This is a quick demonstration of it.
Grasshopper Definition
Rhino Model with input points

Note, that unless you have a quick computer (or a lot of patience), it's probably worth disconnecting at the Mesh component (or disabling) and previewing the surface if you wish to adjust the sliders for variations.

Arc Poly Curve Extrusion boundary Minimal Surface

Grasshopper Definition

There is also capability to restrain mesh vertex to nominated points, curves and surfaces. Some examples demonstrating this will be posted soon.

Cell Filleting a Curve Network

2010-03-16T14:09:00.004Z

Files :
Rhino Model
Grasshopper Model - Previous Grasshopper Model

Files :

Rhino Model

Grasshopper Model - Previous Grasshopper Model

Note that you will need an approved, valid license file for these commands to work. The plug-in can be downloaded from http://www.geometrygym.com

If you find any unexpected results in your own models, please let me know and I will review them.

StructDrawRhino GrassHopper Geodesic Dome

2010-03-08T14:24:00.001Z

This example file demonstrates calling on the SDR Geodesic dome function from within Grasshopper, as well as sweeping structural profiles including member orientation. Try for yourself, but you'll need a valid license (or free trial license) file to do so.

Rhino Model with Profile Property Table

Grasshopper 100406 geodesic dome with structure.gh

Previous Version SDR Grasshopper Geodesic Definition

StructDrawRhino utilised in Grasshopper (2012 Main Stadium)

2010-02-22T19:41:00.006Z

Try for yourself accessing catalogue sections and user defined library of profile curves to be swept parametrically in Grasshopper.

For present, the function is accessed as a c# or vb.net component, and links to a profile section table embedded into a parent Rhino document. If you update a section profile, you must instruct Grasshopper to recalculate (unless a user modifcation triggers a recalculation). There's lot's of planned ideas and improvements to make to this, it's just the beginning (Options for not generating member cap surfaces, root radius fillets etc). If you have any ideas or suggestions, please let me know and I'll try to implement ASAP. This includes requests for any specific aspects included in the StructDrawRhino plug-in or SSI model exchanging tools.

Ensure you have downloaded the latest version of the StructDrawRhino plugin from http://www.geometrygym.com/downloads for this to work, and you must have a valid approved license file (free trial) installed on your computer.

Grasshopper Model File: 100406 2012 main stadium.gh
Rhino Parent Model: 2012 Stadium Rhino Model for GH definition

Cape Town Rhino Users Group Meeting

2010-02-08T06:07:00.001Z

Simply Rhino SA is hosting another Rhino User Group meeting in Cape Town. Jon Mirtschin of Geometry Gym Ltd. will present on utilising Rhino3d for geometrical modelling primarily for architecture and structure. Techniques used to model projects such as the 2012 Olympic Velodrome, Infinity Footbridge and Beijing Watercube will be demonstrated. Innovative tools for geometric modelling including geodesic domes, minimal surfaces, mesh relaxing, tessellation and parametric steel frame modelling will also be featured.

More Details here: http://www.simplyrhino.co.uk/about/RSA.html

If you are interested in this presentation but unable to attend at this time, or are located in another part of South Africa, please contact Jon at jonm@geometrygym.com to discuss the possibility of meeting.

Structure Analysis Model from Curves

2010-01-04T15:21:00.002Z

Try for yourself the routines to generate structure analysis model from curves and points in Rhino.
Rhino Model from here.

Tessellation Work in Progress

2010-01-04T06:54:00.003Z

More on this coming soon...
A demonstration of the work in progress for the tessellation commands in the Rhino3d plug-in. Note I have edited out some pauses waiting for computation to complete. The more computing power you have, the better this will perform so please be patient. Rhino v5 recommended. More performance improvements coming soon and more tessellations.

StructDrawRhino Contouring Colors

2009-12-24T05:13:00.000Z

This screen capture quickly demonstrates the StructDrawRhino command sdrContour to apply a spectrum color range to subLayers of active layer. By typing the command, you can nominate to apply it to Rhino objects in a model (based on sequence of creation/modification or selection depending on how you pick the objects). Download the plug-in from http://www.geometrygym.com

Orienting Structure to Rhino Surfaces

2009-12-23T12:00:00.004Z

Here's an example/tutorial for you to follow to use the plug-in to calculate member orientation angles based on the defining surface normal or nearest point.

To try this yourself, here is the Rhino file: Rhino Ellipse

Now the same basic procedure will work presently with 3 analysis packages, GSA, Sofistik (shown) and SAP2000. Strand7 and others coming shortly.
Here's the analysis models:
GSA
Sofistik (Note LOCA 0 is assumed for the moment.)
SAP2000

More instructions coming soon....

Controlling GSA from Rhino Plug-in

2009-12-21T05:12:00.000Z

There's been a few requests for help with controlling Ansys from Grasshopper or Rhino on the Rhino newsgroup or Grasshopper forum lately, and in my discussions with them, it's generally been agreed that for a skeletal frame, it's likely to be easier and quicker to use a frame analysis program like GSA to do the exercise. (Possibly influenced by my limited experience with Ansys, which is an amazingly capable but complex analysis program).

GSA have a free version for any academics or students, refer http://www.oasys-software.com/information/universities/educational_licences.shtml

And to assist with getting started, I created a small Rhino Plug-in project that generates a GSA model from scratch and runs an analysis.

Download source code : http://ssi.wikidot.com/local--files/examples/rhinoControlGSA.zip

If you have GSA running, you can supervise and interact with the program after execution. If GSA is not running, it will run as a background process.

If you're looking for the GWA data on the rhino model objects created using the SSI tools, try using the command GetUserText (or the user string attributes in the Rhino SDK). I'll improve the event watcher shortly so that GWA node coordinates are updated when a node is moved.

This is just the start of interaction with Rhino, there's another level of using the Plug-in code as a library. Feel free to get in touch if you wish to learn more.

Weaire-Phelan intersecting a surface

2009-12-01T21:35:00.005Z

I responded to a request for help on the Grasshopper forum with regards to generating Weire-Phelan polygons intersecting with a surface. I've recorded the screen capture below showing the difference as you halve the size of the polygons which I think is quite interesting. If you wish to try for yourself, the Rhino file can also be downloaded below, could be interesting to see how other shapes look (and to generate the intersecting curves using the command in the StructDrawRhino plug-in)

Associated Rhino File

British Museum Great Court Roof using StructDrawRhino

2009-11-01T22:27:00.037Z

Another stunning, innovative structure that has inspired similar projects since. It's a favorite space of mine, especially on a bright sunny day when the shadows and reflections are mesmerising.

Here's some papers, blog posts and links I found to determine how Happolds and Fosters designed this amazing roof.

http://opus.bath.ac.uk/14111/1/ChrisDeakin2001.pdf
http://www.enhsa.net/downloads/publi/con2004/102_Williams.pdf
http://people.bath.ac.uk/abscjkw/

So, now you can try to do something similar yourself using the structural plug-ins for Rhino. My routines and commands don't follow exactly the description from the paper, but they allow something similar to be created.

To try this for yourself, the input Rhino file can be downloaded from here

I'm currently coding up algorithms for more powerful force density routines to include dynamic relaxation, but in the interim you can try the sdrMeshRepelVertex command to relax a rigid mesh outline with discontinuitys at nodes/vertices for continuing edges. I used the sdrZigZagCurves command to divide the initial radial lines to generate the starting Grid.

From the starting flat grid, we can use the plug-in command sdrMeshProjectVerts to project the mesh vertices onto the mathematical surface.

Then we start the mesh relaxing process. The command sdrMeshRepelVerts uses force density to repel mesh vertex away from their neighbours. Naked/Free edges/vertex will be restrained. The more loops or iterations you allow, the better the result you will get. Note that you can nominate a target surface that will vertically project the vertex back onto the surface (if you don't, the mesh will naturally flatten). I found the best result was by nominating the balance force option for a number of iterations, and then to run a few loops of the target equal length for edges.

You can then extract the medge edges to curves using the sdrMeshDupEdges command. By applying a structural profile (I assumed a much larger hollow profile than that used), the plug-in will automatically sweep the centreline curves.

There is also a number of routines in development for form finding and finding minimal surfaces. Blog posts with worked examples will shortly follow, but if you look at sdrMinShapeMesh function you can try it for your self. The other sdrMesh.... routines allow manipulation of mesh generated in Rhino to transform it to arrangements more appropriate for analysis/solving.

If you've any requests, ideas or suggestions for these routines (or need more help or other examples), don't hesitate to get in touch.

Infinity Bridge - Supreme Award for Structural Engineering Excellence

2009-10-12T17:25:00.001+01:00

We're so thrilled at Expedition, for structural engineering this award excels amongst the best for peer recognition for design excellence. Infinity Bridge won the 2009 IStructE Supreme Award for Structural Engineering Excellence, to crown it's recognition as the 2009 IStructE Award for Pedestrian Bridges.

Infinity Bridge was competing against over 100 global entries in 11 categories from stadia to public buildings to bridges to private houses.

And this project is a supreme example of the Structural Drawing Tools being developed for Rhino. The arches of the bridge were form found to minimize flexural stress whilst the bridge is free standing, so no pure mathematical curves define the girder set out. Setting out this structure in traditional 2d methods would have been painstaking and inefficient. Current 3d structure modelling software appeared to lack key features to easily generate and manipulate this free flowing curved structure. So we innovated and generated our own tools for our Rhino3D model, that was the principal means of defining the key bridge geometry (which tapered along it's length as well as in section).

Effectively an early version of the current plug-ins, we created tools where a primary spreadsheet generated model creation for both Rhino and Structural Analysis in GSA, ensuring coordination between assessment model and documented structure model.

Extruding along Rhino Curves

2009-10-01T22:18:00.000+01:00

A question raised on the Grasshopper forum for examples/instructions for extruding structural profiles along grasshopper curves prompted me to post a screen capture to you-tube demonstrating the capabilities of the Structural Drawing plug-in.

I thought I'd post the hypar grasshopper file here for those wishing to test it for themselves.

Note that it demonstrates how properties can now be assigned to layers, and that any curve added or modified on that layer will have an updated sweep. For some reason the event watcher doesn't presently identify when the grasshopper bake command finishes, hopefully I'll have this resolved soon.

Oasys GSA v8.4

2009-09-21T07:00:00.002+01:00

Some GSA plug-in users might have been testing Oasys GSA v8.4 beta for some time, others might have downloaded the public release last week (http://www.oasys-software.com/products/structural/gsa/downloads.shtml ) and others might do so shortly.

If you are in any of these groups, you'll hopefully be happy to hear that the Rhino plug-in can already exchange structural data happily with both versions (note there were significant GWA changes I've dealt with). And GSA v8.4 brings some neat new graphic exchange in relation to object colours etc. Always check the wiki (http://ssi.wikidot.com/downloads ) for the latest version.

There's still work to be done, but in progress it's already up and running. Note if you need to update v8.4 model coordinates, you can right click on the export node button and opt for v8.4 format.

In about a week when I'll look to switch the default plug-in to be v8.4 compatible, but you'll still be able to use v8.3 if you're not upgrading. You can edit the export button (by shift-right click) and change the text to make left click export to v8.4

3D Printing and Rapid Prototyping

2009-09-10T21:35:00.002+01:00

David Allgayer has posted an interesting article to the Expedition Blog. 3D printing or rapid prototyping from Structural Analysis models was one of the early principles of writing the structural plug-ins for Rhino (back in the day when it was in Rhinoscript).

I've heard (and repeated) that the day will come when you won't go to a hardware store to buy a replacement shower hook, if one breaks you'll simply load the model on your computer and print a new one to hang on the rod.

The Economist Technology Quarterly Review article can be found here

StructDrawRhino takes on the WaterCube

2009-08-24T22:35:00.009+01:00

So here's my take on to model the Watercube, a stunning stadium if you're ever lucky enough to see it in person.

Download the basic Rhino file from here.

It would have been brilliant to work on a structure such as this. The design consortium included Arup, PTW Architects, CSCEC and CCDI

There's reports on how the geometry was derived here and here that form the basis of my demonstration.

Interpreting Structural Models with Curved and Tapered Members

2009-08-20T21:46:00.007+01:00

The theory and formulation behind structural analysis algorithms and solvers are based on theory of straight elements with constant cross-section.

This means that models representing structural elements curved or tapered in nature are "meshed" or broken into straight segments with a representative cross section property. To my knowledge, any analysis program featuring "curved or tapered members" is simply automating this process behind the scenes.

This results in a side effect that when exporting the structural model to CAD format, that this approximation although fine for the structural assessment, results in jagged and problematic geometry when sharing the model with other designers/clients that don't appreciate this process. (Ie, remarks such as "I like that design but I'd like it without the steps"). For curved elements the segments result in underlap/overlap of the cross section, which is a weak spot if you wished to directly 3d print/prototype the geometry. To date this has generally needed manual remodelling of the structure.

Whilst I believe the better process is to model the curved/tapered structure in CAD and then derive your structural analysis model from this, it's possible to automatically interpret the segmented data (although if precise results are required, you should carefully check the interpretation).

The SSI Rhino plug-in will check each section name for "tagged" descriptions that instruct the plug-in how to "interpret" that cross section. This post looks at the -rhl tag that instructs the plug-in to loft the cross sections.

Download this GWA file representing the summit of the Eiffel tower Download.

Now to create the Mast, simply type -rhl in beam properties 20,21 and 22. The plugin will act on the loft instruction and "join" any sequential elements that have "the same property (or 1 section property either side." The plug-in will fit a curve through the the sequential element nodes, and then orient the cross section curve for each element on this curve at the point closest to the mid-point of the element.
If properties differ by 1 at the ends of the element, the cross-section curve is extrapolated at the start and end of the curve. By adding the "-rhl" tag to property 13, the curved support element for the mast will also be lofted.

Try importing the model into Rhino before and after making the changes, and note the difference. If you haven't had it work as per these images, try downloading this file and check what is different in the section properties. Download

Note that the default iso-curves shown for the nurbs surface are the cross-section shape determined location and orientation.

User Defined Profile Libraries

2009-08-17T22:54:00.014+01:00

I've just uploaded a new version of the Structural Drawing Plug-in with plenty of improvements. I'm preparing to post a detailed tutorial showing how these new tools could be implemented to model the Beijing Water Cube, so watch this space.

The plug-in can now use profile libraries defined by the user. These are simply created by creating (or copying) rhino files into the plug-in sub-folder at C:\Documents and Settings\USER\Application Data\GeometryGym\UserProfiles\ or C:\Users\USER\Application Data\GeometryGym\UserProfiles\ (Note folder may be hidden, and is now reported on the Manage Tab of the main StructDrawRhino dialog). There's an example file there showing some numbers and letters as example profiles (you'll find them now listed in the selection drop down boxes). You can create as many collections of profiles as you like, and they will be grouped by filename (First Selection Box), layer name (Second Selection Box) and object name (Third selection box). The profiles must be located in the model YZ plane, and the origin is used as the default insertion point. A curve can be used to define a simple singular profile, or if it has voids, add it as a planar surface.

The files should allow easily to share and collate your profiles, let me know if you have any suggestions for improvements. Note that if you later rename either the file, layer or object, it will have to be reassigned. Another quick tip, the profiles are now assigned by dragging the first button over your model view (instead of clicking the button as per the previous release).

Generating Structure in Rhino

2009-07-29T11:25:00.004+01:00

Here's the first public version and demonstration applying structure to curves in Rhino using the Rhino Structural Drawing plug-in. More to follow shortly.

Movie file for those without access to YouTube: AVI File

And here's the files to try yourself.
Note that hollow sections won't be hollow if centreline isn't straight (for the moment), and element orientation will be incorporated soon.

Mini-Gherkin Grasshopper Rhino File for Mini-Gherkin

Symmetry and Connectivity

2009-07-01T21:34:00.006+01:00

Here's a screen capture that presents two new tools (amongst others) in the Rhino Structural plug-ins. I've added commentary to this video (feel free to mute if it's too much to bear), but hopefully this might help in following what is happening.

Download the screen capture from here if you can't access YouTube.

The first tool allows you to "contour connectivity", that is to graphically display how many elements connect to each node. This type of unexpected connectivity can often occur when importing and altering models from CAD environments, and a colorful visual check can make the process of verification much easier. Here's an image of the tool applied to the model from this blog post that you can also try for yourself.

The second tool is in the Struct Draw Rhino plug-in, that enables an event watcher (disable it by right clicking the button). This works for any rhino model of points. If any point moves, the plug-in searches for a matching point in the other three quadrants (within tolerance), and adjusts it's position accordingly. This will work for any rhino command that modify's the point coordinate, and can save a lot of work in maintaining symmetry, particularly in structures such as stadia. There's plans to expand the tool so that you can specify any axis (and number of axis) for the mirror planes.

Here's the files to try this for yourself.

GSA
Sofistik
SpaceGass

Shape to Fabrication 3 - London April 2009

2009-06-16T17:44:00.007+01:00

Simply Rhino organised and hosted Shape to Fabrication 3 in April this year.

I've just managed to get a FLV version of the AVI screen capture I presented at this event uploaded to You-Tube that hasn't suffered from compression display problems.

Fortunately/Unfortunately, I don't have the commentary of my presentation on the video, but Simply Rhino video taped each presentation, that they plan to host on their website.

The screen capture starts with showing the structural drawing toolset catalogue sections, including orientation cross sections on a nurb curve and using rhino tools to extrude or sweep the section shape.

Then some Expedition projects are presesented that the Rhino Plug-ins were developed to efficiently and effectively design these projects. Present BIM software capability

Chiswick Park footbridge was designed with many schemes, alterations and design changes. Many manual modelling hours were spent in maintaining and coordinating independent models, (structural analysis model, a 3d CAD model for renders and traditional 2d drawing CAD files).

This inspired the need to exchange data between structural analysis models and CAD programs such as Rhino, with a bespoke plug-in to ensure object attributes are retained and transferred from model environments. The plug-in allows "parametric" modelling where nodes defining member centerline can be transformed individually (or in bulk) using common or bespoke Rhino commands, and this information transferred back to the structural analyis model.

Quite often the scultping required to update to project geometry is not quite as dramatic as this sinusoidal roof, but sometimes it can be. Bulk node projection in Rhino allows a quick and rapid transformation of a detailed structural model.

Infinity Bridge has just opened on the river Tees. The girder profile string-line not defined by mathematical formula as it was form found for the bridge self weght to give effieciency. Combined with a box girder profile that has angled webs and tapers in size along it's length, it is very difficult to setout using traditional 2d drawings comprising plans, elevation and sections. 3d setout was defined in a 3d Rhino model directly used by the fabricator. Structural assessment of the bridge is conducted for each construction sequence state of the bridge, and this information can be directly used in the Rhino model to allow photo-realistic (or sketch) rendering that is very powerful in communication with a client or contractor.

Finally, a simplification of the infity box girder is used to show how Grasshopper can be used to parametrically define a structure (including size, polygon shape etc), and then the SSI plug-in used to generate a "skeletal" model from the baked rhino definition. There are several plug-in commands under development to generate structural data from "primitive" rhino geometry (ie curves, surfaces etc) that allow structural assessment rapidly, even from "sketched" models with loose tolerance in intersections and end connections.

More on Manipulating Structural Models

2009-04-05T09:28:00.014+01:00

Here's the next entry with a tutorial/example on ways of manipulating your structural analysis model within Rhino.

It's been a month since my last post, but there's some great improvements on the way for the plug-ins, and you can see a sneak preview of some of this on the video clip for this tutorial.

Better quality AVI file for those that can't access YouTube or wish to see more detail.

In the current released version, when nodes are moved in the model, the centreline curves and 3d extrusions remain static to the old node positions. To update the geometry, the nodes are updated in the GSA model, and then the existing Rhino representation must be manually replaced by running the interpreter command again.

The plug-in has now been developed with dynamically response to geometry manipulations made in rhino. If you move or relocate nodes in the Rhino, the element centrelines (and shortly 3d extruded representations) will update on the new node positions. Also the upcoming version will automatically replace/update any existing structural data in the rhino file, rather than require the user to manually delete it to avoid duplicate representation.

Anyway, here's some more methods/examples for manipulating your structural model node positions in Rhino.

This example is a simple representation of a bridge, for which we wish to investigate the form and shape.

GSA model: archBridge.gwb
Robot model: archBridge.str
SAP200 model : archBridge.s2k

Sofistik model: archBridge.dat

SpaceGASS : archBridge.txt
Strand7 model : archBridge.txt

And if you want the 3dm file with the parabola : archBridge.3dm

Open the GSA model, and copy all the GWA data from the gateway.

In rhino, right-click on the ssiInterpretGWA button to generate the structural analysis model in Rhino (alternatively you can export the model to GWA from GSA, and left click to open the file).

We don't really need the 3d extrusions at this stage, so either untick the option, or turn off the layers once interpreted.

I'm going to use some point moving commands I've scripted into the latest version of the ssiStructDrawRhino plug-in which you can download from here: http://ssi.wikidot.com/downloads Note that most of the new commands and functionality being developed will only become active when you activate the free trial license for the plug-ins.

I hope to give some tutorials for creating your own RhinoScripts for some of these manipulations in the near future.

The first bulk node manipulation we're going to do, is to move the points to equidistant points on the parabolic curve which represents the arch shape we wish to assess and update our model.

In the structDrawRhino plug-in toolbar, there is a button for the command ssiUtilMovePointsToCurve that will prompt the user for multiple points, and then a curve to move the points onto. During the selection of the curve, the user may toggle whether end points on the curve should be included, and a tolerance for coincident points (useful if your model contains joints with coincident nodes). The command will attempt to sort the points into a logical order, and then update each point position to the corresponding division point on the curve. A confirmation step visually draws arrows and dotted lines representing the changes (you might have to zoom depending on the scale of the movements and overall selection). Once updated (remember the present version of the plug-in won't update the element centerlines yet), you can copy the node coordinates to the clipboard, and then update your GSA model by pasting the GWA data to the gateway.

The video then shows the same sequence having scaled the parabolic shape to give it more height.

Note that the hangers are no longer vertical for our new profile. If retaining vertical hangers is important, we'll use a slightly different , you can mov the vertical hangers in position so that they all interesect the desired parabolic curve. I recommend changing the current layer to a new empty layer, so we can bulk select in a minute. Then run the Rhino Intersect command to generate a point at all of the desired intersection locations. We can then use the structDrawRhino plugin command ssiUtilMatchClosestPoint to select an original and target set of points to match. As the command can utilise a specified maximum distance to move any point, we can bulk select all the structural nodes by right-clicking on the "OasysGSA NODES" layer. Confirm the selection (by enter or spacebar), and then similarly select the newly created intersection points in the second selection. Every point in the first group within distance of a point in the second group will have it's position updated to the nearest, and we can update our analysis model.

Rhino allows so many methods and options of generating/updating point positions that you'll find you're only really restricted by your own experience or ability to learn new ones. Many situations might require manual processing, others will allow techniques such as grasshopper, scripting and all tools and plug-ins available. Some upcoming blog entries will look at these options.

SSI - Structural Analysis Data to/from Rhino

2009-03-01T20:47:00.007Z

SSI (Smart Structural Interpreter) is the plug-in I've been developing that allows data to be transferred to and from Rhino from Structural Analysis programs used by Engineers to assess structural performance and strength. This is currently released for Oasys GSA (which is used at our office at Expedition), and early versions are being worked on for other similar programs.

A lot of engineering time is spent on updating and altering structural analysis model geometry as projects and designs evolve and change. Particularly when different design disciplines coordinate and accomodate to find efficient solutions. By taking advantage of Rhino and using custom and default tools and commands, greater efficiency and productivity can be achieved in updating models.

You can watch this tutorial on this video link, then I'll explain the steps for you to try.

Initial GSA model here.
Initial Robot model here.
Initial SAP2000 model here.

Initial Sofistik model here.

Initial SpaceGASS model here.
Initial Strand7 model here.

You can find the Rhino model with the a surface representing the desired shape here.

Download both these files to your computer. Open the GSA model, but you can skip the step to export the model to GWA (text) format as the file is already supplied as such. Note that all the nodes and elements lie on within a horizontal plane.

Open the Rhino model above, If you haven't already, install ssiGSA and then open the above rhino file. Click on the import GWA button on the plug-in toolbar to import in the GSA model data. Note that you can elect not to draw the 3d shapes for this example.

For this example, we want to move all the nodes in vertical location until they match the target surface. This target surface was generated by the free Math Plug-in by Jess Maertterer.

We can use the Rhino command project which will relocate objects perpendicular to the current cplane until they intersect with a target surface. Only node data coordinates are sent back to GSA, so all the points can be selected by right clicking on the node layer. Type in the Rhino command Project (ensuring you are in the Top view, or that a World Top Cplane is set in Perspective view), and select the surface as the target. Ensure that the original data is deleted so that duplicate nodes are not present in the model. You should see the planar nodes are now all lying on the surface. The updated node coordinates can be obtained by clicking on the second button in the ssiGSA toolbar. The GWA data will be copied to the clipboard, and can be imported into GSA by right clicking on the gateway and electing to paste data. You can manually inspect the contents by pasting into WordPad (or similar text editior). You will see the GSA nodes in their desired position.

Note this is one way of taking advantage of the advance sculpting and scripting environment of Rhino. Upcoming blog entries will take a look at other simple but powerful ways of transforming models to efficiently change structure geometry.

SSI-StructDrawRhino

2009-02-28T18:15:00.016Z

The StructDrawRhino is a plug-in that will be useful for CAD modellers, architects, engineers, and anyone developing Rhino models for construction projects that containing structural elements and representation. The plug-in contains a library of catalogues sections, particularly hot-rolled and cold-formed steel sections available around the world. This catalogue is still being developed so please forward any requests and suggestions through to me.

Here's some instructions to help with using the plug-in.

Once the installer has been downloaded and run on your computer, start Rhino and run the command sdrStructDraw. This will bring up the catalogue dialog (shown in the screen capture below) if it is not already visible. This dialog can be docked in position, or float on your screen whereever is acceptable.

The radio buttons allow the user to specify the insertion point for the section, which will adjust how the section shape will relate to the points the user specified points when adding the structural shapes. The default IP will generally match be the section centroid, except for asymetric shapes such as channels. Top-Middle will orient the section shape below the insertion points.

We will look at adding straight extruded sections initially. By clicking on the Add 3D button, the plug-in command sdrStructDrawElement is run. The user can now select the first point defining the straight line along which the section will be extruded.

After selecting the first insertion point, the user is prompted for a second. The length of the extrusion may be specifed by tpying in the number, and then the second selection point will specify the direction. Before specifying the end point of the extrusion, the user can specify if they wish to specify the section direction point, and the orientation angle in plane for the cross section to be rotated (in degrees). By hitting ENTER when the command completes, it will be repeated. If your desired section shape is replaced (at random) with the SSI logo, you either need to rerun the command, or request a free trial license for the plug-in by running the command sdrZZLicenseRequestStructDraw.

Note in the plug-in dialog box, a Nominate tab is available as an alternative for the pull-down menus of the libary catalogue. A description of the section shape can be entered as a string, in a format consistent with that adopted in Oasys GSA. GSA contains a wizard for creating these shapes, here's an example : STD CH(m) 0.5 0.3 2.E-002 4.E-002 . If you don't have GSA (a trial version can be downloaded), the online help describing this is here.

The plug-in also allows users to add a single face surface, or a perimeter curve of the section shape to the rhino document. The command sdrStructDrawSect will be executed from the other two buttons on the dialog, which will prompt the user to select an existing curve to orient the section shape on, and then for a point on that curve. For this example I have sketched a free form curve, and have oriented a I shape on the start of the curve.

Once the section has been added to the document, it can be used as input to other Rhino commands. For this example, I've extruded the surface along the curve by using the command ExtrudeSrfAlongCrv . The images below show the solid resulting from this operation.

All suggestions for improvements for this plug-in gratefully received. Current thoughts include allowing section specification consistent with other engineering programs, adding more sections (including other countries), and automating process such as section extrusion one existing curve. Please let me know any other ideas and suggestions.

SSI Rhino Plug-ins

2009-02-22T13:34:00.007Z

SSI (or Smart Structural Interpreter)

SSI is the beta branding for some Rhino plug-ins I've been developing for aprox. the past 12 months.

This project started as a response to various tasks and problems that I'd faced as an Engineer working on projects of novel geometry. Primarily this was difficulties in creating analysis models, checking analysis models were coordinated with project drawings, and for coordinating with other design team members, and in how to efficiently describe the geometry of these projects to other team members. But the biggest problem was manipulating models to keep pace with project changes and evolution. Although analysis software has made progress in this area, the methods were still largely manual and time consuming. And part of the problem was that primarily all our drawings were done in 2D (plans, sections, elevations), and the CAD tools we used were focussed on this nature of drawing.

When I arrived in London and started work at Expedition I was introduced to Rhino3D, which is an amazing 3d modelling environment. Rhino has many attributes that make it a fantastic tool for a designer, and I'll list a couple. It can import and export so many CAD file formats (including Microstation and AutoCAD), it has an amazing support group of advanced users on it's newsgroup that will offer advice for everyone from beginner to expert, and for a scripter/programmer, it offers an excellent environment to allow automation and customization for generic and specific problems.

So the two initial plug-ins I've been developing for Rhino are an importer/exporter for structural analysis programs, and a catalouge structural section drawing tool. I'll provide some instructions/examples for using these plug-ins in my following posts. The importer/exporter allows automated drawing and updating of a 3d structural model without the need for manual interpretation and coordination. It also provides advanced tools for efficiently manipulating and generating structural analysis data from within Rhino, so that analysis models can take advantage of the more sophisticated sculpting ability of Rhino than exists commonly in analysis programs. The structural drawing plug-in is basically a sub-set (or by-product) of the first plug-in, that allows designers to manually extrude structural members, or easily add structural sections to rhino documents from a library of standard profiles.

Structural Modelling In Rhino3D

2009-02-22T09:18:00.005Z

Here's some thoughts and opinions that I've formed in the 3 years I've been using Rhino to model structure and construction that might hopefully inform and assist any newer Rhino users reading this. This is intended as a brief introduction to some of these topics, many of which I expect will form the basis of future posts.

COMMANDS

Many users like to operate Rhino primarily using the toolbars via their mouse, but of course commands can also be run from the menus, or by typing commands (or shortcut aliases) in the command window. Primarily this is the way I work, and the blog posts will generally refer to commands by their command name (hopefully this allows readers to find references in help files easier), with some menu references. If you're a convert from CAD programs such as AutoCAD or Microstation, you'll probably be reluctant to learn a whole new suite of commands (however similar they may be) for Rhino. The good news is, you won't have to. I would highly reccommend using an rhino alias to allow you to use command names/shortcuts that you are already familiar with, and most importantly allows you to use multiple cad environments simultaneously without frustration. To do this, use the menu Tools-Options-RhinoOptions-Aliases. A simple example is assigning an alias id to '_evaluatept

TOLERANCE

Rhino commands and tools work to a tolerance that is specified by the user within each Rhino Document, and it's quite important that designers are aware of this and have given thought to the tolerance before they start modelling. Problems due to a "loose" tolerance can emerge at later stage of project design, particularly when the model is used as an input to other uses such as rapid prototyping, or Finite Element Analysis. I would highly recommend setting your tolerance as tight as you dare, and relaxing it when necessary if commands such as the boolean operations, intersection, splitting etc are failing.

The default tolerance is specified in your Rhino Template files. Because Rhino is used in so many industries and purposes, the installed defaults should be edited for your purpose. You can save your own defualts by opening a new document in your required units (ie metre, or milimetre etc), go to

Here's the Rhino wiki entry on tolerance.

CONSTRUCTION PLANES AND MODEL

It's common practise in CAD to model construction projects in worldwide position (ie OS coordinate system). In Rhino, I'd strongly recommend keeping your model in space close to the origin by using a local project axes system. You will likely observe display problems if you use a coordinate system with coordinates of a large value such as those typical in OS. This is because Rhino uses numbers of "single" precision for display mesh positions. But you can set up named construction planes (similar to User Coordinate Systems in AutoCAD) that will enable you to interogate or specify coordinates in your model in large coordinate systems.

Working effectively with geometry for Construction Projects

2009-02-20T15:49:00.007Z

This is the first post (hopefully of many) that will provide tutorials, examples and provoke discussion for effectively generating, manipulating and assessing geometry for construction projects from stadia, to bridges, to buildings, to roofs, to anything else that is built.

It will primarily focus on using Rhino to effectively design construction projects, and explain how to take advantage of some tools I am developing, that utilise the amazing scultping and modelling environment within Rhino3d. The plug-ins I am writing create efficient ways of drawing, generating and manipulating models representing structure, as well as exchanging the information back and forth with structural analysis packages. I have set up a wiki for the plug-in, that can be found at http://ssi.wikidot.com

I hope and encourage anyone reading these posts to contribute comments, suggestions, alternatives, and to request topics and tools for further development. I'm expecting that the blog will cover all sorts of topics, from how to draw and model in Rhino, how to write your own RhinoScripts to Automate tasks, parametric modelling using Grasshopper, and we'll see what else.

Cheers,

Jon