Weirdly the excellent devblog that I got all this info from[1] mentions crazy compression algorithms for the vertex animation and for the level files, but not specifically for the occlusion data.

[1] https://all-things-andy-gavin.com/2011/02/02/making-crash-ba... Especially part 3.

I think occlusion was just per vertex.

From the blog:

> Our occlusion worked on a texture level. That is, if we had a giant polygon with a fern texture on it (think many leaves but lots of empty space) the occlusion could actually get rid of polygons behind the leaf part of the texture but leave the polygons seen through the alpha channel holes. No other game had that kind of detail in occlusion, and it paid off immensely. Given how small ground polygons could be in the distance, a little fern action went a long way.

There's a video series on YouTube where game devs talk about the challenges they faced while driving the game. Crash Bandicoot is covered in one episode, and there is another fantastic episode about Dead Space with the tentacle scene. Much recommended view.

There's quite a few videos.... Can you link to the specific one your thinking of? Cheers.

I'd guess that they are referring to this video by Ars Technica https://youtu.be/izxXGuVL21o