V-Ray direct caustics bug

[Chabb]

I encountered a strange bug while trying to render an eyeball with caustics using MODO 11.1v1 and V-Ray 3.52

These are screenshots of a simplified scene.

Refracted caustics part has the color of shadow (as defined in spotlight settings), directly visible caustics part is very noisy.
I didn't find any combination of vray settings to make refracted caustics detail match the reference one

Any suggestions?

[boyan]

Hey, Chabby,

Thank you for the feedback. Did you check the result with bucket render? Also, I encourage you to check the document section here: https://docs.chaosgroup.com/display/VRAYMODO/Caustics

May, I check the scene file as well? You can download the latest official 3.6 with new Caustic render element built-in.https://download.chaosgroup.com/down...to12-36001-adv

[Chabb]

Those images were made with adaptive sampler (modo 11.1v1 + vray 3.52). I sure checked that document section about caustics, but got no ideas what may be wrong in my case.
Default settings at least produce some result with large scale (like pools),
but with this test scene (lens is 11mm in diameter) the only results were very blurred or completely black in refracted area and very noisy in directly visible area.

[boyan]

Hey, Chabby,

Thank you for the feedback. Check the re-worked scene file.



Happy rendering

[Chabb]

Hey, Chabby,
Thank you for the feedback. Check the re-worked scene file.

Thanks a lot. I'll check it asap. The preview you posted still looks blurry, but the noise is gone at least.
What was causing the noise?

[boyan]

The preview you posted still looks blurry, but the noise is gone at least.
What was causing the noise?

You've increased Caustics Subdiv. of Spot Light to 4000 (1000 is defaulted value)

If you want sharper result you should decrease the photon quantities. But I think it is realistic - because you have a lens only.

Cheers,

[Chabb]

You've increased Caustics Subdiv. of Spot Light to 4000 (1000 is defaulted value)

If you want sharper result you should decrease the photon quantities. But I think it is realistic - because you have a lens only.

Cheers,

The thing was to make caustics look similar too the native modo render one.

So I set spotlight caustic subdivs back to 1000 and got black spot. Hmmm.
Though the increase of max photons setting helped to get rid of it.

Also I'm curious whether "show calculation phase" option should work like that,
showing traced samples not only while calculating, but in a final render too. But only those which are directly visible by camera.

[juanlalupa]

I also trying to render caustics in V-Ray for modo following tutorials from max users but is hard to get similar results, have you figured out how to render caustics properly?

[Chabb]

I also trying to render caustics in V-Ray for modo following tutorials from max users but is hard to get similar results, have you figured out how to render caustics properly?

It's something to do with the scene scale. Large scale (pool-like) looks nice. See attachments. caustics MODO11 VRAY352.zip