badnormals

A tip on rendering out water simulations

Added 2021-10-20 16:04:12 +0000 UTC

As I am currently preparing the 3.0 geometry nodes video, and the intro features a water simulation, I had the problem with rendertimes. It was two hours per frame. So sadly I wasted quite a bit of money on a renderfarm with no result :(

But to make sure this doesn't happen with you:

Don't use cycles native motion blur when you are also using foam/spray/bubble particles. This slows the render down massively. Instead use vector blur in the compositor, for that you have to enable the vector pass under render passes. Also under mesh baking, check "generate speed vectors" and under simulation baking set the cache type to uni. OpenVDB doesn't work. This way you can get a lot faster motion blur. The native one also looks pretty strange with foam. One problem you might encounter are some weird trails of vector blur, to fix that set the maximum speed limit to your taste.

Hopefully this saves some of your time.