# Mesh shape tension (Catenary Surface)

Hello, Im having trouble trying to get the edges of this mesh to be pulled further in. I’ve tried increasing strength in different areas but nothing works. Its more circular than refined. Im modeling Frei Otto’s Dance Pavilion. Any help would be appreciated. This link takes you to a shape diver on what its actually supposed to look like,https://app.shapediver.com/m/form-and-forces-3-frei-otto-dance-pavilion
A1.gh (35.2 KB)

Some of your goals could be set up in an easier way…

The eye for example can be defined with just edge lengths. You don’t need anything more for it, the height is adjusted by the tension in the mesh.

I’m pretty much always using an entwine component for the goal inputs. Then a tree branch component on the kangaroo output to get branch 0;0

My definition is still missing a cable from the outside edge anchors towards the center.

A1.gh (43.0 KB)

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I didn’t look through the whole definition, but for the Kangaroo part, the issue was that you had the boundary edges of your starting circular mesh fixed in X and Y.
This means it was like finding the shape with its outer boundary constrained to slide up and down along a rigid cylinder, which doesn’t make sense for the form-found structure as there would be nothing in reality providing the horizontal reaction force of this virtual cylinder.

Also, with the Length goal if no input is given to the ‘Length’ input, it defaults to its starting length as the rest length. Here it makes more sense to give it some pre-tension. You can also control the boundary edge separately to have more control over the shape, as you would with boundary cables in the structure.
A1.gh (40.4 KB)

The upstream part of the definition does look a bit more complicated than it needs to be to generate a radial mesh like this.

For example, here’s one simpler way
simpler.gh (11.6 KB)

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Thank you! This completely fixed my problem. The simpler way is what I ended up going with and reworking all of my other stuff with it. All the extra stuff is so I could end up variating when needed but nonethless was way more complicated than it should have been. Thanks again

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