Issues rendering spherical harmonics

[nickpaustian-slv]

I have a very simple scene setup using the library via npm and it works perfectly, until I enable spherical harmonics.

I have tested the model in the online viewer (https://projects.markkellogg.org/threejs/demo_gaussian_splats_3d.php) and it works there so I am sure it is something to do with my setup so I am still working through debugging, however I thought I would ask in case someone can point me in the right direction.

The code that loads the splat:

private async loadSplat() { this.splatViewer = new GaussianSplats3D.Viewer({ threeScene: this.scene, renderer: this.renderer, camera: this.camera, useBuiltInControls: false, sphericalHarmonicsDegree: 2, })

this.splatViewer
  .addSplatScene(plyUrl, {
    position: [0, 0, 0],
    rotation: composedRotation,
    scale: [100, 100, 100],
    progressiveLoad: false,
    showLoadingUI: false,
  })
  .then(() => {
    this.splatViewer.start()
  })

}

[mkkellogg]

Would you be willing to share your .ply file? Maybe I can do some troubleshooting on my end.

[nickpaustian-slv]

I believe I have uncovered the issue, it looks like the spherical harmonics are affected by the scale of the splat scene.

Here is the same splat at a lower scale:

and at a scale of 1:

I think I was using a higher scale to work with some other objects I had in my scene, but I should be able to scale those down to work with the splat instead.

[mkkellogg]

Thanks for figuring this out, it turns out I didn't take the scene's scale into account when rotating spherical harmonics (I just assumed a scale of <1, 1, 1>). I'll include a fix in the next release.

[mkkellogg]

I made an update in the 2dgs branch that should address this issue, want to try it out? You should be able to scale the scene now without affecting the spherical harmonics.

[nickpaustian-slv]

Thanks @mkkellogg, that is working great now when scaled.