I made csg from 2 extruded polygons to subtract, but got unexpected result.
Could you kindly explain your question a bit more to clarify the issue?
the result should be a capped mesh, not uncapped.
CSG can’t guarantee good results if the meshes have big overlapping areas like the ones in your examples.
I change the intersection, still not right
I was confused about the polygons for a second, but get it now, you’re using an improperly extruded polygon. The shape should always be in counterclockwise order, you could still see a “filled” result then because of doubleside, but this impacts the extrusion. Here’s an example with a properly extruded polygon: extruded polygen subtract | Babylon.js Playground (babylonjs.com)
many many thanks!