How can I keep the bevel modifier from creating ngons and tris? I thought a quad-only mesh would do it, but it doesn't like topological gems, and the edge flow is too important. Or is it Simply Imposible ?
I don't think there is any automatic way accompanied with Bevel modifier to operate like that. Some other manual solutions:
- If you just want to triangulate, there is a Triangulate modifier for you to use;
- You can also select all faces then CtrlT to convert them into Triangles;
- If you want to keep quads as many as possible, select all ngon faces only, by Select > Select Face by Sides, set it greater than 4 (As shown below), then CtrlT to convert all selected faces into triangles, then AltJ to convert them into quads by tweaking Max Angle in F6 panel.
The Bevel modifier uses Tris and ngons to create the bevel itself, in order to reduce any unnecessary vertices that you apply the modifier to any complex object; you should select your object, tab into edit mode, go under the tool bar and hit remove doubles. This will significantly reduce the amount of unnecessary vertices.