I'm trying to learn to create models using non-destructive techniques, so I'm using a lot of boolean operations. For this workflow I create some primitives, and they each get the last material added to the object I most recently modified. When I boolean the primitives together, existing faces retain their materials, but new faces get a material assigned at random. Rerunning the same script several times produces otherwise-identical meshes with different materials on some faces.

Why is there random behavior with materials? And is there a way to control what material is used by booleans?

  • $\begingroup$ Are you actually interested in why, or do you want to know how to make it stop? $\endgroup$
    – Kirbinator
    Jul 3, 2023 at 0:27
  • $\begingroup$ Both, really. I'm quite lost as to why the boolean API would include random behaviour, which seems obviously bad to me. $\endgroup$
    – Densaugeo
    Jul 3, 2023 at 19:05


You must log in to answer this question.

Browse other questions tagged .