OTOY Forums

Answer is:

https://www.facebook.com/groups/OctaneR ... 4693498266

It is currently possible (to some extent) via e.g the Specular Material and (recommended) PMC Kernel. The PT kernel is capable of converging "sharp caustics" but is inefficient at it, PMC helps but PPM, as posted by promity, is the ideal [upcoming] solution.

PMC with, for instance, parallel samples to 1 and some other settings, should produce plausible and pleasing results, albeit PPM would be more efficient and suited for caustics.

Elsksa, could you please point me at any info on these settings for better caustics? I'm rendering bottles and desperate to get some good caustics but I've tried the PMC kernel and it doesn't seem to make any difference?

batman911 wrote:Elsksa, could you please point me at any info on these settings for better caustics? I'm rendering bottles and desperate to get some good caustics but I've tried the PMC kernel and it doesn't seem to make any difference?

It should be rather straight forward in regard to the PMC render settings I did mention above. The other factor is the mesh geometry and lighting. The latter has to be strong and sharp enough to produce the wanted results. It is also needless to mention that the scale of the scene has to be plausible.

Could you share and attach a screenshot of your scene?

Thanks Elsksa, here's the IPR Render, the attachment of the basic scene and what I'd like to eventually produce on the Ballantines whisky photo. I know the liquid is wrong on the upright one but it doesn't really effect the overall situation. The issue is that the caustics are way too basic and blurry. It isn't just the scene, every time I do caustics and glass with bottles I have the same problem. Any ideas would be greatly appreciated

Thank you for the additional information.

"Sharpening" the lighting should produce the wanted result. In other words: avoiding a large and soft light sources (that produces soft shadows) will be necessary for such imagery.

There's only one small very bright light in the scene so I don't know what else I can do, as you can see it's also not able to calculate properly with lots of blotches everywhere?

If you think the light is small, then I would bet 100% the scale of the scene is incorrect. Scale unit is arbitrary, yet, scale matters a lot in rendering. It is highly recommended to work at the real scale.
A wrong scale can result in many rendering issues such as in shading e.g. SSS for characters, to be set to (sometimes extremely) uncommon values. Up or downscaling the camera can result in other issues affecting how the rays are traced (thus, affecting data AOVs for instance among other rendering aspect) and changing the scale will mess with the transforms too which can become very annoying to fix when interchanging assets between different 3D DCCs. To just name a few of the resulting issues...

The bottles must be out of scale and too big (meters high perhaps).

Just to be clear, Octane is capable and many have done it before (and the new kernel will greatly improve this aspect). If it does not produce the expected result, it is likely coming from a "user error", so to speak.

Let me know how it went after double-checking the scene-scale.

Thanks Elsksa, the scene is the correct scale, I've attached the zip file of the scene.