I don't know on that Vue issue - Depending on the rest of my scene, more than 3 to 5 and my machine used to 'buy it' before I upped my memory from 1gb to 2gb. Every figure added adds a lot to the memory usage - keep your 'task manager' (Win) or 'activity monitor' (OSX) going while running Vue and watch how your memory creeps up.

That was not replicated figures though, but distinct individual fully clothed figures like in this image:
That one was a real memory problem for me back when I did it, which ended up costing me a day of rendering.

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