Hi Sotiris,

Sorry @agakorz14 I missed this discussion the first time around.

For an initially flat strip like this where the thickness is very small in relation to the width, the deformed shape should closely approximate a **developable strip**. There is unlikely to be significant **in-plane** bending or stretching.

If we are just considering the shape it bends/twists into for a certain combination of end positions/orientations, and it is not significantly affected by self weight, then this shape does not depend on the material stiffness.

Although the beam goal does now support anisotropic bending resistance, I think it is not well suited to something like a strip where the aspect ratio of the cross section is this high.

Alternatively, you can treat the mesh as a shell, and use hinge goals to resist bending, with strong length goals on the edges to prevent in-plane deformation. This is probably the best bet for now, and has been used with reasonable success to model thin strips before, for example here:

https://www.researchgate.net/publication/289707025_Form-Finding_and_Design_Potentials_of_Bending-Active_Plate_Structures

Because the bending won’t generally happen exactly along the mesh edge directions, the stretch resistance will also slightly affect the bending resistance, but this effect can be mitigated somewhat by using a fairly dense unstructured triangular mesh, as can be generated with MeshMachine.

The downside of this method though is that because quite a dense mesh is required, it can get slow for long strips.

Another method I’ve been experimenting with is the discrete geodesic nets as described in this paper from IGL

https://igl.ethz.ch/projects/developable/

Because it separates the bending direction from mesh direction it allows the use of a simple quad mesh.

Here’s a definition if you want to have a play with it. It probably needs more work though, particularly in the way the bending resistance is calculated.

developable_strip_igl.gh (30.4 KB)

Yet another technique I’ve looked at more recently is a quad mesh only 1 quad wide, letting the shape of the quads change as it deforms to follow the bending direction, but keeping them planar and preserving the overall unrolled shape using the angle and length sums. So far I’ve had only limited success with this, but will update if I get it working better.

Anyway, if you have a more specific question or example, perhaps I can help set something up.