Object Pooling with static object

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Hey,

I was wondering whether I could use Object Pooling with static Objects, like street lights. As I have about a couple thousands streetlights in my scene (300 triangles on each triangle) in my Scene. Currently they are combined into a couple big meshes and marked as static to reduce draw calls, but I was wondering whether i might just be able to use around 10-20 street lights in an object pool.

So as I want them to stay static, I wonder whether moving those as static objects will have a big impact on performance. Or if it might be worth trying to use those 20 street lights as non-static objects.

As far as I see it I will increase the amount of draw calls by 19 if I use 20 single street lights instead of one big mesh with all street lights in it. But those will be 20 meshes with 300 triangles instead of one mesh with maybe 34.000 triangles. I now many people say that draw calls have a big impact on performance so I try to avoid using to many, but I have a hard time to understand how the big mesh can be faster then then a couple more smaller meshes.

1 Answer

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By its nature object pooling will not work with objects marked static. The whole point of marking an object static is to tell Unity I’m not moving this object. The point of an object pool is to move objects constantly instead of creating and destroying.

An object pool is perfectly reasonable to use for street lights. As long as you have a method to tell when you no longer need each light you will be fine.

As to the draw calls issue: A big mesh is faster then multiple smaller meshes of equivalent size. A big mesh will not necessarily be faster then multiple smaller meshes with a significantly smaller size. Benchmarking is key here. In general I have seen object pooling as a solution for garbage collection. I haven’t actually seen any data on its results on graphics performance.