I have created this test scene with 6 object, with a total of 3444 faces (7000 tris) and I just want to bake a 4k AO map.
It takes 2m 45s to bake with my RTX 3080 (which seems insanely slow to me), however if I join all the objects so it becomes on single object, then baking only takes 40s (which still seems slow to me).
How can being separate make it 4 times slower?
One reason this can happen is because when you bake multiple objects, Blender restarts a new baking process from the start for each object, redoing the scene building each time. However, I wouldn’t think It would make such a big difference in a small scene like this.
What are your baking settings? are you doing a bake type that gets denoised? Because I am thinking Blender may be denoising the result of each object separately, which could explain the time, especially if the prefilter is set to accurate mode (an AO map should denoise fine with “none”).
I am using the emit bake type, and denoise prefilter was set to accurate. Will check in a few days, when I’m back at my computer, if disabling denoising changes the baking time disparity with multiple objects.
