Hacker News new | ask | show | jobs
by cubefox 61 days ago
> but I could imagine a hybrid mode where certain elements like grass and shrubbery are drawn with gaussians

Those tend to move in the wind. Animations don't work well with splats. Or with any data structure except polygon meshes.

Edit:

Responding in the parent because HN says I'm "posting too fast" and should "slow down".

> Have you seen https://www.4dv.ai/

Yeah, but this seems to be just a 3D GS video (captured from several different camera angles), similar to how an ordinary 2D video is just a series of still frames. For 3D games this would be unsuitable since animations often have to be generated on the fly based on game physics. Even for pre-baked animations the memory cost of loading each frame individually would be too inefficient. For polygon meshes you have just a single static mesh that is deformed over time.

> Dreams managed to animate splats on the PS4. Admittedly, not quite the same type of splats, but there is probably a middle ground here where it can be made to work

I'm pretty sure Dreams only allowed animations as translations and rotations, not something that approximates soft skeletal animations. And even translations and rotations would be problematic since 3D GS scenes rely on baked lighting which would then result in objects no longer fitting the scene.

2 comments

Have you seen https://www.4dv.ai/
Doesn't give much information about how they were generated
The example they gave of 4d splats used a room with dozens of cameras, and it only talked about the software used for 3d, not 4d.

For the outdoors examples on that site I can only assume they used dozens of drones?

> Animations don't work well with splats

Dreams managed to animate splats on the PS4. Admittedly, not quite the same type of splats, but there is probably a middle ground here where it can be made to work

Dreams uses SDFs though?
Dreams uses SDFs to generate splats on the GPU - all the actual rendering is splat-based.

Alex Evans gave a really great talk about the whole tech stack, the PDF is here: https://www.mediamolecule.com/blog/article/siggraph_2015