Motion blur defaults

[romullus]

I did some test today and found that increasing MB segments doesn't hurt performance at all. In some extreme cases it's even opposite - default settings takes longer to render and looks awful. Is there a reason why MB transform and geometry segments are set so low? Maybe i'm missing something?

[atelieryork]

Interesting find... I wonder if it's because, with more segments, there is less contrast between the pixels, therefore less work for the engine to do?

I was doing some long-exposure renders to produce car light streaks recently and will try again now with much higher segments and see how it affects things.

[Ondra]

well if you take an extremely fast motion example, do not be surprised that extremely high samples count work well. But if you would take slow motion example, low samples count would work better. And most motion is slow. So there ;).

[romullus]

Well, what do you know! Just did additional tests and my practice confirms your theory :]

[Ludvik Koutny]

It's also worth noting that while Motion Blur samples may not decrease performance, they definitely increase memory consumption. You won't see it much in a simple scene with single propeller, but in large complex scene where many things move, setting MB segments high can cause running out of memory very quickly ;)