I love these kinds of posts. Simple, fast, AI-free, and I learn something new.

I'll accept any kind of jocularity in the current climate!

Isn't the same as just taking every triangle from the mesh, calculating the volume of a prism-like polytope between it and its projection on one the planes, and then taking it with a + sign if its projection is oriented in one direction, and with a - sign if it's oriented in another? This kind of formula works based on the basic geometry.

My belly says the naive formula is summing the triangle pyramid volumes to the origin with sign in orientation. It looks like that's what they derived. Which is a generalization of 2d polygon area calculated by summing triangle areas for each edge, I was taught this in a math camp where we calculated map polygon areas on gis data. I remember math knowledge being hard to get pre AI era but I didn't remember it being this hard.

No idea what the author means by "which are equivalent to rendering the mesh and then sampling the render".

Did they also work on the graphics stack for the Asahi project?