Hi all,
I’m trying to optimise my scene by reducing the number of draw calls as much as possible (targeting Oculus Quest).
I notice that my Terrains seem to be creating a number of draw calls and I don’t understand why.
For example ‘Terrain 5_4’ seen in the screenshot below (highlighted in yellow) is a fairly basic Terrain, with no grass details or Tree objects created on it, however the Frame Debugger shows that it currently requires 10 draw calls!
Would someone be able to explain why a Terrain like this requires this many draw calls?
Is there anything I could do to help reduce the draw count?
Many thanks in advance :)!
Not all draw calls are equal in terms of their performance impact. You’ve first got to use a tool like RenderDoc to see what % of your frame time is spent dealing with terrain, and if that’s actually a sensible amount of time or not. 10 draw calls are fine if they’re quick, one draw call is a problem if it’s very slow. For what it’s worth, 54 draw calls doesn’t actually sound like very much to me, but if you’re having frame rate issues to do with graphics then the first question is always: are you GPU bound or CPU bound?
A large object like terrain can be split into multiple draw calls because that’s what is actually optimal, and the way it does that depends on what your batching settings, how many triangles the mesh/submeshes are, and what your Shader is (the default URP one, in your case). But if that’s not the case you may want to consider a smaller Terrain or a terrain object that doesn’t use Unity’s terrain system and uses plain meshes instead.
Hey Matt, thanks for your reply!
You’re absolutely right and I’ll definitely take a look at renderdoc to see what’s taking up time and if there’s anything to be improved upon there.
Thanks also for your explanation on why a terrain might be split into multiple draw calls (regardless of whether that actually hinders performance). The terrain in this case is reasonably small, but it could be that I’m using more triangles than is actually necessary for the size! I’ll see what the settings are and make sure that I’m not using more detail than is required visually.
Thanks again for your help, I really appreciate it! 