Hi,
I am currently experimenting with models by Frei Otto. As you can see, the results differ compared to a rectangular mesh when using a diagonal mesh. My hanging model is similar but primarily differs near the free edges from Frei Otto’s model. What might I be doing wrong?
Frei Otto Hanging Model.gh (58.9 KB)
Hi @Mario_B
Yes, the orientation of the mesh edges will make a big difference to the shape of a hanging net.
There are a number of other factors that will affect the shape.
When you start with a flat grid there are several ways you can allow it to hang:
-One is to strongly preserve the edge lengths (by giving them a high strength) and move the corners inwards.
-Another is to keep the corners fixed and increase the rest length of the edges while keeping their strength high. This will give the same shape as the first option, but at a different size.
-A third is to keep the corners fixed, the rest lengths the same, but use a lower strength for preserving the edge lengths. This simulates a more stretchy grid, unlike the first 2 options which can be thought of more as a net of chains. This will give a smoother shape with more variation in edge lengths.
The difference between 1/2 and 3 is more apparent when using a diagonal grid compared to one aligned with the boundaries, as for the diagonal grid, strict edge length preservation leads to ridges and even wrinkles, which doesn’t occur for the aligned grid.
Playing with the sliders here will show this:
hanging_diagonal.gh (12.3 KB)
Aside from this there’s the question of whether you fix a single point at each corner or a row.
Also it isn’t totally clear from the image, but it looks like maybe in that model there are different loads applied along the outer edge?
I had the same thought 
in this image the outer border is absent. The “cells” (squares in the grid) are open.
I’ve modified Daniel’s solution and removed triangle faces of the mesh
hanging_diagonal.gh (26.4 KB)
@maje90 Indeed, you are correct, the outer edges are missing. Instead, he tied the ropes at the edges together.
@DanielPiker Unfortunately, I don’t have any other information about the load distribution, but since the net is being loaded by icicles, it is entirely possible that the load increases towards the free edges
