Rendering over 15 million splats

[DANNYXU24]

This is a stretch, but I am working on building this VR environment. So far from all the other gsplat renderers I've tried, yours has the best performance/outcome. 10 models of 150,000 splats (1,500,000 splats total) work fine in VR and there is no lag, but when I scale it up to 100 models (15,000,000 splats total), there is obviously big lag issues. So, I know this is a stretch, but do you know any potential fixes that can possibly help with the lag. I am using URP and XR.

[wuyize25]

Sorry for the late reply, and thank you so much for the positive feedback!

There are several ways to optimize performance: use Single Pass Instanced mode and disable MSAA. Currently the sorting pass does not do view-frustum culling — I might implement that later (but not soon) to avoid sorting splats that are off-screen, which would also help performance.

However, rendering 15 million splats is definitely a demanding task; even with the optimizations above the frame rate may still be low. A more effective approach is to use LOD: when an object is far away, switch it to use fewer splats for representation.

[DANNYXU24]

Hey thank you for the response, do you know how I could add LOD to splats? From my knowledge, the built in LOD on unity only works on meshes. Thank you for your help and hope to hear back.

[wuyize25]

Unity’s built-in LOD Group indeed does not support components other than the built-in Renderers. However, you can create a dummy Renderer (for example, a completely transparent cube that encloses the gsplat object), assign this Renderer to the LOD Group, and then write a script that, each frame, toggles the GsplatRenderer’s enabled state based on that Renderer’s isVisible property. You may need to preload the gsplat assets; otherwise, there might be a lag when enabling a GsplatRenderer. Alternatively, you can also implement your own custom LOD controller specifically for gsplat objects.