Chamfer normals trick


A little trick how to chamfer geometry edges with just one face and get good results. It was originally invented by Arenshi, a good friend of mine, I just made a script to automate it and decided to share the knowledge.

The problem is that default face smoothing behaviour in modeling programs (at least in 3dsmax) is simple averaging and it gives you quite buggy looking results if you only use one face for chamfer, so you are forced to use many polygons, and it is still not perfect:


The solution is to manually select each original face after chamfer and straigten it’s normals:


This way your faces remain straight, while chamfers interpolate between them. And you can use just a single face! This is very useful for game low-poly models.

Finally, here’s a tiny MaxScript that automatically chamfers all edges based on angle between polygons and fixes all normals this way:

I haven’t time to add any UI to it, so to use, you have to select an Editable Poly object and run it. Chamfer amount and threshold angle are hardcoded and set to 1 (chamferAmount variable) and 0.85 (chamferAngle variable, range is from 0 to 1).
Script is not greatly optimized, but usually runs quite fast.