IES Lights only with GI Brute Force Rendering?

[cedric_vaucher]

After inserting some IES lights, the rendering got jagged. I removed every setting progressively to pin point the issue. As far as I can tell, progressive rendering is not compatible with IES lights. That's very odd! Is this a known problem?

[sirio76]

IES files works fine here using both BR and LC and progressive or bucket sampler. I've experienced some issue in the past with some older Vray builds and with some specific IES files but that was related to the adaptive lights, using full evaluation usually solve the problem. Try to use the latest build of the software and if the problem persist try to use a different IES or disable adaptive lights.

[cedric_vaucher]

Thanks for your quick answer. I am currently using Vray 5.20.04.
I have tried different IES without improvement.

What do mean with "disable adaptive lights"?
I tried the override settings and it seems to work: Render Settings / V-Ray / Overrides / Lights Overrides / Light Evaluation Mode / •Adaptive Lights •Full Evaluation
I will do some further tests later on.

PS
Does "Full Evaluation" mean longer render times?

[sirio76]

Does "Full Evaluation" mean longer render times?

Usually with only a few lights there is a little difference, once you add hundreds or thousand lights you can get a huge speedup using the adaptive lighting.

[valentin_leondiev]

Hello cedric_vaucher

During my tests, the IES lights worked consistently with Light Cache and Brute Force regardless of the sampling method and V-Ray engine.

Can you share a bit more information, regarding this issue?

1: Can you share a few screenshots or a screen recording showcasing the issue you are experiencing?
2: Are you rendering with CPU or GPU (CUDA / RTX)?
2.1: If you are rendering with a GPU, please provide me with the exact Nvidia Driver Version you are using.
3: Can you please share the exact V-Ray for Cinema 4D Version you are using?
3.1:You can find the exact version of V-Ray at V-Ray dropdown > Help > About > Right click text and select the copy text option and paste the information here.

Example: V-Ray 5 for Cinema 4D, Update 2.2 (v5.20.02 from Feb 21 2022)

Please note that the date of the V-ray build is important to us as it can help us understand when exactly the issue originated.

4: Does this behavior occur with every scene you try to render, or only a specific scene?
4.1: If it only occurs with a specific scene, can you please provide us with the scene in question along with all associated assets?


If you are not feeling okay with sharing the scene publically on the forum, you can message me directly with a download link or open a ticket via the Request Form.

[cedric_vaucher]

1: I've trashed all failed renderings since sirios help.
2: Rendering on CPU OS X, iMac and M1 Max Mac Book.
3: V-Ray 5 for C4D, Update 2.4 (v5.20.04 from April 2022), as mentioned before.
4: It happened with the one scene as soon I added more than one IES-light. Then, erasing all but one light didn't help (one way). The solution described by sirio76 was helpful (see above).
Unfortunately, I can't replicate the problem. All kind of render settings, normal maps, etc. seem to work now!?
I suspect the problem may also be caused by normal maps and/or displacement tags...

[aleksandar.kasabov]

Hello cedric_vaucher,

I apologize for the delayed reply.

I am glad to hear that the solution, provided by Sirio helped.

Please let us know if you manage to reproduce the issue again so we can investigate further. Thank you.