Thanks a lot Mark the essay is great and very useful,
Have you come across a script or a grasshopper definition using the shortest/geodesic path function?
You have mentionned in your essay that Buro Happold developped their own tool for that?
Have they made it available?
Do you know an example of built gridshell where this geodesic curve logic is used for its structure?
I am currently working on a large gridshell with engineers and looking at different ways to articulate/pattern modify our Rhino NURBS Surface, we have tried a regular square tiling and a parallelogram tiling as i thought these were the most common options...
is that really the case?
Ah...in that essay as published was before I was able to consult with Buro Happold, Los Angeles on that same project. They use Tensyl for the form finding, I then applied the geodesic curves on their surface from Tensyl, and then they did some analysis of the geodesics I placed using Robot. There were some significant differences between the relaxed surface in Tensyl from the one I was able to generate with David's plug-in, and then the real interesting, though obvious in hindsight, was that in the second iteration in Tensyl an upward force was applied appropriate to the arching action (bending strength) of the wood lath, and voila - the resultant looks much more like a catenary arch. Attached is a PDF of a slide showing this that I presented at the conference (the section is cut obliquely to approximate a section along one of the geodesics).
Sorry for the delay Arthur, I just found the "follow" button to be notified when this thread is commented on. Anyway.....The process I went through was to develop a basic 2d X-grid, and "apply curves" to the surface, then I used these endpoints on the two long edgecurves for my endpoints for the "shortpath" or geodesic. A little convoluted but it worked.
This is exactly why I would love to see a shortpath command in grasshopper, as this would open up opportunities to iterate where the two points are best placed.
BTW....sounds like you are serious about gridshells, I have IL 10 on gridshells scanned as a PDF - huge file, but priceless research now out of print and impossible to find. You can email me but not appropriate to upload here.
Glad you like it:)
Steel gridshells always seems to be triangular and i am currently working on a large one.
The definition i posted is not triangulating the shell which is why i have to mesh things afterwards.
How did you deal with bracing in the several gridshells you have worked on ?
How would you deal with triangulation if this was necessary?