Game Optimisation: Several small or few large?

I have a dilemma for game optimisation. I read somewhere that Blender renders a single large object faster than several small ones for a given number of polygons. However, I expect it is easier to cull smaller objects, so you probably win that way.

So here’s the question: Let’s say I have a forest scene with thousands of trees (which I do and it runs OK but I want a better frame rate). Am I better to have all the trees (crossed billboards) joined as a single object, each tree (a pair of billboards) as a single object (= thousands of objects in the scene graph) or somewhere in between (groups of trees joined as objects)?

Likewise with the terrain. Currently it is a single large object with many polygons. Is it better to break it up into smaller tiles or leave it alone?


Thanks for that - very interesting.

So it looks like bundling similar objects together does have a performance gain. In my case but some break-up might help because at the moment the single trees mesh is always in the viewing frustum even if individual trees are not. So, if I break it into big chunks I should be able to save myself a lot of polygons per frame.

Do you know if these improvements (e.g. the LODs etc) will be coming to BGE 2.64… or soon?