Rasterization when using sh3

[murcje]

Hi!

I am experiencing a rasterization issue when using spark on my platform. The splat looks good in https://sparkjs.dev/viewer/ but on my platform I get this horizontal rasterization.

When I use an sh2 file there is no raster.

Here is the ply: https://storage.googleapis.com/voluma-assets/voluma/testestes/PM_Lykke_250KSplats_Cropped_Compressed.ply

And here is the ply on my site, with rasterization:

https://voluma.ai/embed/voluma/testestes/lykke

[dmarcos]

Thanks for filing. We'll look into it

[mrxz]

@murcje These "rasterization lines" aren't due to spherical harmonics but are caused by quantization. Looking at the provided .ply file the splats all have Y coordinates < -210, which is quite a way away from the origin. I needed to drag the camera a lot when loading it in the viewer, but saw the same artefacts. Could it be that when you tested it in the viewer you used a different file?

In any case, I would recommend adjusting the splat file so that the splats are near/around the origin and also to try and keep your SplatMesh close to the origin of your scene as well. That should yield the best results and avoid most quantization issues.

[murcje]

@mrxz I believe you are right. The splat was created by a client of ours. It is positioned at about +210 on the y-axis.
I placed the group of gaussians on the origin and the artefacts are gone.

Thank you for taking time to check!!