Should an octree be rebuilt every frame?

Question

When using an octree for collision detection in a game, should the tree be rebuilt every frame or is there a better way assuming half the objects move in a frame?

Answer 1

If you have a lot of static geometry in your scenes, consider building separate octrees. You could also express the same idea by having more complicated leaf nodes that differentiate between static and non-static geometry.

Bottom line: only regenerate what you have to.

Answer 2

If the scene changes with every frame, then you have to redo the tree.