Disabled collection slows down rendering extremely

Hey Folks,

I have a pretty heavy scene with around 40 mio polygons, multiple view layers and multiple deactivated collections. When I render this scene it takes around 2.5 minutes per frame. I then deleted the deactivated collections for testing purposes and my render times went down to 1 minute per frame.

I was wondering if this is intended behaviour? I thougth that during the pre-render-process only elements in activated collections get loaded in RAM/VRAM and are rendered?

Would be nice if anyone could explain this behaviour a bit further

It’s difficult to tell what’s going on without specific details, which specific visibility setting are you referring to? Hide, disable, exclude?

Generally speaking anything invisible will not make it to Cycles, but hidden objects may still be evaluated by Blender if visible objects depend on them. Additionally objects hidden in the viewport are not necessarily hidden in final renders, there may be multiple view layers with visibility settings, etc.

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sorry that i wasted your time, it was a complete unconnected compositor node tree, that still got executed for whatever reason and slowed down the rendering

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Its not a waste of time, We need some sort of a run-time profiler (I am sure its easier said than done due to endless factors that needed to be taken into account).

I am probably not the first one to mention the need for such tool.

We also need a better way to display hierarchy and relation between data-blocks to easily spot dependencies, The current viewing method in the outliner is a bit cluttered.


yeah that would be helpful