United3dArtists Archive

I have a complex face on a model with a large number of edges. I need to make that edge all rounded. The chamfer and fillet tools just can't handle anything beyond simple shapes that are all convex. Get any concavity along part of the face and it'll foul up the geometry where it changes or it'll just give up on most of it and only do two or three edges, or it will crash trueSpace.

Pop in a cylinder, select the top face and fillet. It works. Same for a cube. Start again but copy the cylinder and move the copy a bit, subtract to make a crescent moon shape and try to chamfer or fillet the top face. Complete fail, geometry hideously trashed.

Pop in a cube, copy and move up, subtract to make a L shaped block. Select the edge at the inside of the corner then chamfer. Looks OK but zoom in and you'll see the fillet is shorter than the block with a tiny bit of the original inside edge left at each end. Fail again.

Something that it does work on. Pop in a cube then a cylinder. Scale the cylinder down some and raise its Z position, subtract from cube. Select face at bottom of the hole then fillet. It works! Doesn't blow up the geometry or crash. I suspect that it would fail on a hole with complex shape at its bottom face.

To properly work on edges meeting at any angle, a chamfer/fillet plugin would have to do something like bisect all the angles at each vertex then figure out the distance 'down' perpendicular from the selected face and plot back from that level to construct the geometry, lofting up the angle or curve with its top at the same level as the selected face. Sort of how the bevel tool (that mostly works well, except on tight spots where the new edges lofted from bisected angles cross) works but "in reverse", pushing the original edges 'down' instead of shrinking the original face and pushing it up.

Makes me think the programmers didn't think of 'reversing' the bevel process when they created the chamfer tool. Filleting could be an iterative bevel process, chamfer distance divided into X number of reverse-bevel operations divided into 90 degrees to set the angle for each.

Interesting. It is a little hard to visualize, do you have screen captures?

For smooth edges/corners I run some SDS modelling, using new loops right by the edge on each corner I want to fillet or chamfer, then run the SDS accordingly. If I need to make the model lighter, I don't have to SDS the whole model, just the edges.