Hello fellow Houdiners,

I’m running into a rendering issue that I can’t seem to figure out. I’m working on a moving paint effect (using FLIP fluids) inside a glass object.


The problem: no matter what I try, my renders always come out grainy. I’ve already increased the primary samples to 128, rendered at 4K, and even tried using the ODIN filter, but the noise persists.






To troubleshoot, I:

Hid the glass object (in case it was causing the issue) → no change.



Disabled the filter (in case it was introducing artifacts) → still the same.



Tried multiple combinations of render settings → nothing helped.

At this point, I feel like I might be missing a specific setting or option.

For reference, I’m working in Houdini 19.5.368 (I haven’t moved to H20 yet since FLIP fluids changed there and I’m not comfortable with the new workflow).

Does anyone know what might be causing the persistent grain in my renders, or what settings I should double-check?