hello! I’m fairly new to Rhino, I’m more used to work on SketchUp to draw models and calculate the fabric by my own way. However, there is a structure I usually work with that I seem to be failing on the measurements, as when it is installed, it’s never properly tensioned, and sometimes there is an arch between edges. I was advised to work on Rhino with Grasshopper, because I could maybe design the structure and simulate the fabric to see where the error could be, before I send it to the seamstresses. But most of the structures I find were shade sails and nothing that could help like this, so that’s why I’m here! I hope to find some help so I can properly test it.
My question is… is there a way to test with types of fabric? I usually work with a couple different ones that have different tensile resistances until it ruptures (from 250 N to 670 N). My goal is to make it as tensile as possible, without causing unnecessary arches.
I haven’t been on Rhino in years so I feel really rusty, as I wasn’t in the area for so long. I attach photos of the model I made on SketchUp!
I will keep testing, my issue is that the fabric isn’t simulating the shape I want, probably because I followed a canopy/shade sail tutorial, and the fabric doesn’t adapt to the shape I designed for the structure! Maybe I am missing something, or maybe it is just my very lack of understanding. Am I missing something?
I’m not an expert for form finding and fabric simulation but I’ve done a fair bit of grasshopper work in this field. There is no straightforward way to simulate fabric unless maybe you use a plugin
If you are going for cutting pattern you will need something dedicated like Rhino membrane or the likes. If it is just some formfinding you can go with kangaroo( s far as I know it is not suitable for cutting).
Actually it is possible to calculate these tensile structures with standard Rhino tools, but it is a bit involved.
What you get is the amount of stretch of the solution. With that you can decide which type of fabric fits best to get a nice anticlastic shape with the desired pretension.
Not sure what you mean, but the seam cuts of theses pieces are not straight.
If you mean the lower edges and if these are not fixed (just the corners) then they have to be curved.
Thank you, this helped a lot! For now, I will use Kangaroo to just find a fitting, but will also work around Rhino membrane, in case we wish to test on an actual structure.
Thank you very much, Jess, I believe I have found a way to test, but still unsure how to try with different textiles that isn’t PVC, but that’s more of a case to study and work on my end !
As for what I meant about the arch between edges, I meant in the real structure we work on. From the sides, it is perfectly stretched, but the back and front tend to always create an arch, either immediately or along the time, and we have tried with different types of PVC, but it seems to be an error on my end when I design the fabric. So I will keep working hard to find a solution with the help of Rhinoceros, it seems to be a good solution!
I attach the photo of my test in process, of the metallic structure, and now to test how the fabric would behave once stretched to fit without issues. Hopefully it will work out this time, so thank you so much everyone for helping!
If these edges are straight then they cannot create stretching forces to form a membrane (overall negative curvature). Have a look at the white arrows:
You may also dive in Rhino’s Surface Curvature Analysis tools. These help to design a nice membrane surface. Check attached file: CAD_Kay_jM.3dm (1.2 MB)
