> My belly says the naive formula is summing the triangle pyramid volumes to the origin with sign in orientation. Yeah, that would also work but it's a slightl

> My belly says the naive formula is summing the triangle pyramid volumes to the origin with sign in orientation. Yeah, that would also work but it's a slightly slower formula, sum(det(v1,v2,v3))/6. This one is summing sort of prism+pyramid shapes made by projecting each triangle to the yz plane.