Hey, been playing around with the new updates.

When i render in the viewport, takes around 5-7 minutes which is nice.
Offline, can take around an hour (the image with the black background).

Things are still noisy.

And the results are imo wildy different to the point i cannot judge the result based of viewport alone.

Is this by design or is this a discrepancy?


cheers

The differences are likely due to firefly clamping (“Color Limit” parameter). In 18.0, karma offline rendering uses per-component sampling which takes multiple SSS samples per camera ray and averaged, so spectral scattering with high amount of contrast is less likely to get clamped and cause tonal shift. You can increase “Color Limit” to fix the problem in IPR. There's currently a bug in 18.0 where changing this parameter seemingly doesn't do anything unless you restart the render - we'll be addressing it very shortly.

Needless to say, offline and interactive rendering need to look identical, color-wise and contrast-wise, without the artist needing to manually ensure settings line up to make this true (e.g. having Color Limit affect offline rendering only). Most tweaking will happen using the interactive mode and so having the look change when rendering offline is highly undesirable. Coarser sampling may be acceptable for interactive purposes in some cases, but definitely not color shifts like this.

Agreed. This (among others) is the reason why next major release of karma will have a setting to decide the sampling behaviour so that both IPR and offline rendering produce identical result.

Thanks for the responses guys

Houdini 18.0.503 Fixed a bug in karma where changing Color Limit in display options would sometimes fail to update in IPR.

Cheers guys, gonna test it

Partially Tested.

Looks almost identical already. And IPR for me has sped up a lot.

The color limit was set to 10 on both. Those fireflys are almost non-existent. The SSS effects has diminished but i will tweak that. Massive step forward in my eyes.

Great job.

These images are at 100% btw