I am not a chamfer/export, but is this supposed to fail? Yes, I cant achieve the desired result with a BoolenDifference, but it would be great if ChamferEdge just worked.
In Fusion 360, this is not an issue:
chamfer.3dm (2.6 MB)
Hi Rudi - Correct, that will fail to trim in Rhino - do you see how to fix this in Rhino after the fact?
(ExtractSrf trim, Join) If you are reporting a bug it is generally most helpful to post a file in the state before the bad thing happens, so that we can reproduce the problem. But I think here in Rhino adding the chamfer before the holes is the way to go.
-Pascal
The (known) shortcoming is that ChamferEdge only consideres the surfaces that are attached to the edge being chamfered (or filleted with FilletEdge, or blended with BlendEdge for that matter). If the operation touches other surfaces in the polysurface, like it does in your case, it will not complete, but give you a start point for manual work to get where you want to be.