A 3D Tiles dataset consists of multiple nodes organized into a 3D spatial tree structure. The root node of this tree defines the top level entry point for visualizing the tile dataset. When zooming in the root node is checked to see if it needs to split to increase the level of detail shown on screen. This check is delicate: split a node too late and you see low quality data on screen. But split a node too soon and you spend too much time loading data that has no visual impact. It is a classic speed versus quality problem.

The parameter that controls the splitting of a node is called the “geometric error” and each node in the tree has a value for it. If the geometric error is large the node splits early. The most detailled nodes (leafs) of the tree have a very small geometric error.