Let us say that there is a rectangle - R1 - and another rectangle R2.
R2 is complete inside R1.
So R2 face is overlapping with some part of R1.
How can I remove the overlapping part because when I export the model and use it there is z-fighting?
Forget about following answer, (due to me missing the Dev. category)
There shouldn’t be any Z-fighting, R2 should have a rectangular face that you can select and R1 should have sort of a “window” face that you can select separately. SketchUp would normally split R1 as soon as you draw R2 coplanar over R1’s face.
Make profiles visible to at least 2 points to see if R2 shows profiles instead of thin edges.
Sorry, I missed the important detail. R2 is a group.
Can we do some kind of post-processing to tackle this problem?
R2 needs to be created as a component with glue to plus cut opening properties to that specific face, instead of a group. Try that in Ruby.
Shouldn’t need a cut-opening. The Glue To should take care of the z-flighting. (Internally it’s offset a little bit when rendering)