generative modeling for Rhino
I've been trying to develop a free-form mesh surface through form finding procedure, by using Jon Mirtschin's very interesting GSA plugin (http://geometrygym.blogspot.com/).
I've studied some examples I found pretty useful, but I am kind of stuck, maybe in the final phase of the process; is anybody capable of checking the ghx file and try to help me solving the impasse?
I hereby enclose the ghx, and a sketchy snapshot of the result I've been seeking; thank you all so much in advance,
Here's some comments from my look at your model to keep you progressing.
Your sketch shows continuous curvature over the lines of support, in reality a membrane or fabric would crease and hang over these support lines (as my image shows). If you wish to "form find" this type of geometry, you will need to find a way to apply upwards pressure at these regions.
It's easiest to work with a single mesh, so I reworked your line generation to loft a surface (there were some internal disjoint edges forming). Also, I added an exaggerated gravity load case to give the surface shape (with settlement loads only, the surface will relax to a minimal surface, which will produce planar type surface in your example as it spans one way. I also added an xy restraint to the internal nodes not vertically fixed, the surface was collapsing at some edges causing problems in calculating a result.
One other tip, if you right click on an ssiBake component, you can disable the placement of data into Windows Clipboard that will help accelerate the process.
I hope this helps you progress further closer to your objective, I'm happy to help advise further.
Thank you so much Jon, you've been very kind and helpful! Thanks to your very good clarifications, next days I'll develop further aspects of the project, I'll think about the best strategy to deal with it and I'll keep you up to date if you wish.
Best regards, Alessandro.
I've been developing further stages of the project; my aim is to morphogenetically modify the initial shape I designed, in order to find an optimum structural shape with minimal bending stress, strain energy and deformation.
I can't understand what I'm missing, I worked following your suggestions but I have difficulties in getting good results, can you take a look at it?
thanks in advance, Best regards, Alessandro.
Great to see your progress.
In order to effectively troubleshoot this type of problem, I suggest disabling the "solving component" and using the ssiBake component to manually take model to GSA and try running the analysis task there when you can supervise it.
When I did this, I first tried taking the planar restraint of the internal nodes (using a similar test that you did to place them on the perimeter). Still no luck, the form finding was still producing strange and diverging results. So the next thing I checked was your model units and it seems that's the issue. You either need to adjust material units for an 80cm wide mesh, or I took the assumption it was 80m wide and changed the rhino document units. Then I started getting results.
From your initial shape (and note to minimize flexural stress), I'm assuming you might like a vaulted (shell) shape rather than a membrane, so I've form found against a positive gravity load in the attached. I also increased the maximum acceptable cycles, it was so close to convergence for 10,000
Hope this helps,
Thanks again Jon, very helpful as always! Now, with your precious suggestions I hope to update you soon on further interesting developments.
Best regards, Alessandro.