mending broken batwings
it’s always the little things that screw you up…
in this case it was a set of surfaces that had been accidently duplicated, and also flipped the wrong way. when you explode the polysurface you can clearly see the extra faces :
so you delete them, then join the surfaces together again into a polysurface:
now we have a surface with all the faces facing the right way. so we mesh it:
now the thing about modeling minimal surfaces like this in Rhino is that they’re not really minimal surfaces…. you can see here in the rendered view that the batwing as these sharp edges… minimal surfaces aren’t supposed to have any sharp edges….
In this next image you see 3 batwings: from left to right – 1: original mesh with sharp edges. 2: welded mesh (angle tolerance of 180) – smooths out some of the edges but not really. and 3: the orignal mesh just before the next step….
So now we’re going to use David Rutten’s classic mesh relaxation script to smooth out this batwing a bit. it’s not going to give us a pure minimal surface, but at least it will look more like one. Before loading the script, make sure you weld your mesh, or else it will explode like when Jen tried it:
so here we go: load the script, then select “Geometry Links” –> then select the “‘Exterior” node filter. this sets the edges rigid so that other parts of the surface can relx out, while maintaining the edge shape. Select all the outside nodes, then select “Fixed”
Now hit “Relax” and watch it jiggle -
Offset the mesh:
check it :
You can see the difference in the surfaces really shows up in the render: (L-R) 1: Original Mesh with sharp edges, 2: welded mesh with slightly smoothed edges, 3: Relaxed mesh, 4: offset solid of the relaxed mesh.
on a side note, I found some old photos of making a similar surface by HANDCUTTING a heap of boxboard… ahh, life before laser cutters….