Draw calls - A few 'simple' questions

Development Rendering
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Hey guys, a few questions ranging from super basic so I know my foundational understanding is ok to a bit more complex:

  1. I have a wooden pole using one material / one material slot. The material in the slot is a material instance (2 drawcalls in total for the mesh and material right?) If I duplicate this pole 300 times in a scene, I will still only have 2 drawcalls? OR, do I need to merge actors to gain this advantage? OR, am I completely wrong?

  2. I have a unique mesh which isn’t going to be duplicated, using 9 different material slots (10 draw calls right?) The 9 material slots are all filled with tileable material instances and taking from various trim sheets, is this more efficient than using a single 2k texture in one material slot? (just 2 draw calls?) I realize this question depends on the situation, just wondering if anyone has any insight. I’m developing for Oculus Quest 1/2.

  3. Mesh Draw Calls + Draw Primitive Calls - Are these the only stats I should be looking at on the console? I assume Mesh Draw Calls gives me all the information I need for Mesh + Texture, and then Draw Primitive Calls is everything taken into account.

Cheers in advance for taking the time

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there have been plenty of talks about this and you can find a bunch of tuts on yt on how to optimize your scene

  1. one drawcall means a mesh + material combo. that means if you have 2 meshes with the same mat you have 2 dc. if you have 1 mesh that has 2 materials on it you have 2 dc. and so on.
    regarding mesh instancing i remember at some point this became the default in UE4 but im not sure if it applies for sm added to the level and duplicated around or if its for sm inside actors (bp), not sure. i read somewhere that this change was going to make ISM and HISM obsolete…
  2. its always better to have one material than 9 but if those tileables are reused heavily then it might outweigh the large drawcall hit. it depends. best way here is to make one material with a blending mask (rgb or index map) that combines all those trims and tileables.
  3. you should also take into account everything else and at the end of the day steady fps is all that matters, not drawcalls.
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