Your Godot version:

Godot Engine master. godotengine/godot@4364ed6

Issue description:

@tetrapod00 I have a draft of the process for making manifold shapes using Blender's fixing tool. https://docs.google.com/document/d/11KPDwMuZl3c4NSwanhatekAIvUxktURmXJVPkP_a17o/edit?tab=t.0#heading=h.r41iui30hwv7

Let me know if I should work on it more.