What is the purpose of buildSplatTree function?

[nerpa87]

Hello, thank you for sharing great viewer!
I have a question about buildSplatTree function in SplatMesh.js - it seems that during tree building much resources could be consumed in case of scenes with big amount of splats. This makes viewer crash on mobile devices.
However viewer works without buildSplatTree, can you please explain what is the purpose of SplatTree building? What for parameters maximumDepth and maxCentersPerNode are responsible?
Thanks in advance.

[mkkellogg]

The splat tree is an octree structure that enables performance enhancements in a couple of ways:

1. It is used to speed up raycasting
2. It is used to help cull splats that are outside the view frustum so they they don't get rendered

maximumDepth is the maximum depth for the octree and maxCentersPerNode is the maximum number of splats to store in a node before splitting the node into 8 sub-nodes and recursively applying the algorithm to the child nodes.