It's quite possible that they make heavy use of instancing, which might reduce the memory footprint by a lot. Not every pebble or rock needs an individual geometry.
From the video it sounded to me that the 100s billions of triangles were from single instance geometry. The models they mention in the video are in the ball park of >1 billion triangles each (that's 12 Gb per model). So if they have 100 models of that resolution, that's 12 Tbs, and whether they instance each model 1 or 100 times doesn't matter much because the problem of having to fit those 12 Tb in triangles somewhere still remains.
That's why it seems much more plausible to me that they are not storing triangles anywhere, and instead just storing geometry images.
If one mesh is 1 billion triangles, and you have 100 different meshes, you need to store 100 billion tringles, unless you do something radically differently.
If you have 1 triangle mesh, and instance it 100 billion times, you don't need to do that.
> "more than 33 million triangles."
The assets the company they mention makes have 100s of millions of triangles, and billions as well. So I wonder if they are not using those original assets after all.
IIUC they are, but they are only rendering at lower triangle counts and the LOD happens automatically.
