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**natalia.gruzdova** · 26-06-2023, 08:10 AM

Hello glennco,
Thank you for your post.
Please see my answers below:

This issue has resurfaced
Light mix & light texture problem - Chaos Forums
https://forums.chaos.com/forum/v-ray...ure-problem

Currently, it seems to be reproducible only if changing color (not intensity) of the lights in Light Mix and then clicking To Scene. Can you please confirm this or share if you have noticed any other scenarios as well?

Using CUDA (CPU & GPU) production/progressive rendering, GPU usage went to 50%, was 100% under Vray6.

Could you please share how you monitor GPU usage? If you use Task Manager for this purpose, please check this article on how to do it correctly for CUDA render engine: Monitoring V-Ray GPU performance on Windows. As stated in the article RT cores can not be monitored in the Task Manager and different apps should be used.

Also with LM high GPU VRAM around 8GB, without LM 5-6GB.

You have shared that you have a large number of lights in your scene and Light Mix is expected to require memory and how much memory is needed depends on the complexity of the scene.

I cannot share the file due to NDA.

We can also provide you with an NDA agreement that can be signed by both sides guaranteeing that the file is going to be used strictly internally and for debugging purposes only.

Alternatively, you can delete all sensitive information from your scene before sending it to us, for example to test Light Mix we might not need geometry.

**glennco** · 27-06-2023, 06:37 AM

natalia.gruzdova
Thank you for your reply, sorry for my delay I am very busy for the next couple weeks.
Thanks for mentioning the color change, I may have done that.

I cannot share the file.

I use task manager for general GPU monitoring. When I need precise information I use HWMonitor.
I observed the GPU at around 50% for the entire rendering in this file.
Other files the GPU is 100% with some times down to 90% briefly, then back to 100%, I have an 8700k so probably some throttleing.
As well after updating to 6.1 the views took at least 2x longer to render compared to vray6.
side note this doesn't impact the lightmix problem. The reason I use task manager is that Rhino frequently continues to run after exiting, and I have to end task to stop it. I reported the issue to Rhino forum, they said disable Vray. Which I can't do since I earn a living making renderings. When another user posted same problem that doesn't have Vray, Rhino mod's stopped responding.

I checked some newer files I created with V6.1, and I can't see the light mix problem there, so maybe legacy conversion is part of the issue.
That could be a problem going forward if/when I continue with projects that are older.

To make a neon sign from a logo, I start with emissive material, slot a clear background PNG with white logo into top slot. Then in slot 3 (transparency I think?) I slot a JPG with white background and black logo.
GOBO light project uses rectangle light with JPG black background and white logo, directionality at .998

I noticed in V6.1 light mix groups all emissive materials as one, even if they have unique names. So, we cannot adjust them individually. I do set LM to group instances so that copies of lights are grouped together, but unique groups are seperate from other groups. Whereas emissive are 1 group for all emissives.

Glenn

**natalia.gruzdova** · 29-06-2023, 04:46 AM

Hello glennco,

Thanks for mentioning the color change, I may have done that.

We have logged this issue as VRW-4089 and we will post on this topic once there is an update on this matter.

I use task manager for general GPU monitoring. When I need precise information I use HWMonitor.

First, please make sure to check the article I have shared in the previous post and perhaps test the GPU-Z application as well to track the GPU usage.

I observed the GPU at around 50% for the entire rendering in this file.

Other files the GPU is 100% with some times down to 90% briefly, then back to 100%.

Unfortunately without your file we can not be sure if the issue is scene-related or not, because we need to test it in our environment to see if the same behavior can be replicated.
Alternatively, we could arrange a TeamViewer session to take a look directly at your setup, if this is a plausible option for you please open a ticket using this submit request form so we could send you instructions on how to book a session.

As well after updating to 6.1 the views took at least 2x longer to render compared to vray6.

Have you made any changes in the file after the update? Please note that in order to correctly compare two V-Ray versions it is essential that the same scene is tested, with no changes in terms of geometry, materials and settings are applied. If this is the same scene,but for example with more assets, materials, different settings, different camera views it may be expected that it renders longer.

In any case, please test your performance with V-Ray Benchmark in V-Ray RTX and CUDA modes and share a screenshot of your results.

I noticed in V6.1 light mix groups all emissive materials as one, even if they have unique names. So, we cannot adjust them individually.

Currently, there is no individual emissive materials selection in the Light Mix, all emissive materials are stored in the Self Illumination Layer.

Announcement

Vray 6.1 light mix problem AGAIN

Vray 6.1 light mix problem AGAIN

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