Tuesday, 16 June 2009

Shape to Fabrication 3 - London April 2009

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.