dispersion caustics?

Forums: dispersion caustics?
A public forum for discussing and asking questions about OctaneVR.

dispersion caustics?

Postby madcat117 » Sat Sep 11, 2021 4:36 am

madcat117 Sat Sep 11, 2021 4:36 am


madcat117
 
Posts: 33
Joined: Thu Oct 08, 2020 9:22 pm

Re: dispersion caustics?

Postby promity » Sat Sep 11, 2021 7:49 am

promity Sat Sep 11, 2021 7:49 am
AMD Threadripper 1950X/64gb ram/RTX 3080 Ti + RTX 2070/Samsung SSD 870 EVO 500 gb/
Lightwave 3d
User avatar
promity
Licensed Customer
Licensed Customer
 
Posts: 363
Joined: Sun Dec 19, 2010 7:59 am
Location: Russia

Re: dispersion caustics?

Postby elsksa » Sun Sep 12, 2021 9:39 pm

elsksa Sun Sep 12, 2021 9:39 pm
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
Licensed Customer
Licensed Customer
 
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Re: dispersion caustics?

Postby batman911 » Wed Oct 06, 2021 8:35 am

batman911 Wed Oct 06, 2021 8:35 am
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
Licensed Customer
Licensed Customer
 
Posts: 28
Joined: Wed Sep 11, 2019 12:09 pm

Re: dispersion caustics?

Postby elsksa » Wed Oct 06, 2021 1:37 pm

elsksa Wed Oct 06, 2021 1:37 pm
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?
elsksa
Licensed Customer
Licensed Customer
 
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Re: dispersion caustics?

Postby batman911 » Mon Oct 11, 2021 7:58 am

batman911 Mon Oct 11, 2021 7:58 am
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 :)

Caustics forum render.jpg
Basic render setup


Ballantines Caustics example.jpg
Caustics example photo
batman911
Licensed Customer
Licensed Customer
 
Posts: 28
Joined: Wed Sep 11, 2019 12:09 pm

Re: dispersion caustics?

Postby elsksa » Mon Oct 11, 2021 12:41 pm

elsksa Mon Oct 11, 2021 12:41 pm
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.
elsksa
Licensed Customer
Licensed Customer
 
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Re: dispersion caustics?

Postby batman911 » Tue Oct 12, 2021 7:42 am

batman911 Tue Oct 12, 2021 7:42 am
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?
batman911
Licensed Customer
Licensed Customer
 
Posts: 28
Joined: Wed Sep 11, 2019 12:09 pm

Re: dispersion caustics?

Postby elsksa » Tue Oct 12, 2021 1:47 pm

elsksa Tue Oct 12, 2021 1:47 pm
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.
elsksa
Licensed Customer
Licensed Customer
 
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Re: dispersion caustics?

Postby batman911 » Thu Oct 14, 2021 8:24 am

batman911 Thu Oct 14, 2021 8:24 am
Thanks Elsksa, the scene is the correct scale, I've attached the zip file of the scene.
Attachments
Caustics Test Bottle.zip
Lightwave Scene files
(1.5 MiB) Downloaded 156 times
batman911
Licensed Customer
Licensed Customer
 
Posts: 28
Joined: Wed Sep 11, 2019 12:09 pm
Next

Return to OctaneVR Questions & Discussion


Who is online

Users browsing this forum: No registered users and 8 guests

Thu Mar 28, 2024 11:47 pm [ UTC ]