Oh nice! I didn't realize those kinds of effects were possible without SH
Are the baked in reflections technically bug or is it fundamental in some way?
They’re fundamental to the scene if you recite light transport and not just geometry. Gaussian splats are just a clever way to sample a lightfield and reflections are part of the lightfield.
Well it's more that I'm asking if lighting data should live entirely in the spherical harmonics. It's certainly feasible and common in the game world.
...But maybe that doesn't make sense in the GS context.
Yeah splats can encode view dependency without SH, but not with a correct geometry. E.g. often, you see reflections encoded in GS as just a 3d scene on the other side of the mirror. Other view dependency effect can make the surfaces "fluffy", etc. This is not great when you also try to get decent geometry.
That said, I don't think SH are the best way to represent view dependency. Other approaches using MLP or deep features seem more promising.
We just found that splats encode some view-dependent shininess anyway (for example the guitar body https://playcanvas.com/model-viewer?load=https://code.playca...) and so considered the extra data and rendering cost of SH not worth it for now.
It would be quite straightforward to add SH to the PLY file and we'll definitely consider it in future!