Hello Houdini friends,

I got a problem with rendering flip fluids in Mantra. I keep getting (black) flickering in my renders. I tried all kinds of settings and upped my samples etc. But without any good results. I hope someone here can tell me what to do to fix this.




Pixel Samples: 6 | 6
Min Ray Samples: 1
Max Ray Samples: 8




I changed these settings

- I turned on “sample lock”
- At Ray Limit: Use Direct Lighting as Background
- Raytracing Bias from 0.001 to 0.01

Hi mate,

Did you try rendering just the ocean surface on it's own? without foam, spray?
It almost looks like a foam issue. Maybe check to see what the foam rasterize looks like…?

Or turn off diffuse contribution in the ocean shader and see what happens…

Another parameter you should check when rendering ocean surface is the antialiasing on the shader itself
under displacement>Anti-Alias blur

Thank you for the reply!


I will check if that's the problem. I'll come back on that on Monday.

I turned off the “Diffuse Contribution” and set the “Anti-Alias” to zero. But It still got back spots in the flip fluids. I tried teh water only to, but that was the same.

I'm going to make a new flip fluid, ocean animation. And check if that one does work.

Again, thank you for the reply/tips.