Rendering Multiple Mesh Light Instances

[james_morvay1]

I posted here not long ago, about a question I had dealing with multiple lights in a scene and how Vray renders them. Case in point, I have a scene I am trying to render, where there are multiple instances of one mesh light (created as a component). I have tried multiple options for rendering, from my RTX graphics card up to using the Chaos Cloud (wasted credits). For using RTX enabled progressive rendering, I get "blocks" of inaccurate lighting (same holds true for the Chaos Cloud version). It should be noted that this render scene contains a lot of glass panes. I couldn't tell you off hand how many but the panes of glass have been created a components, depending on the size (which there are three different sizes. I applied a thickness to the glass (about 1/8"). Could it be that the blocking effect is due to the glass having a thickness, and if I changed the glass to have none, or rather made into a simple flat surface), would that change the way the rendering come out?

I feel like I am out of options here, but it's vitally important that I get this scene rendered, and need to have the glass present, as well as the multiple lights. I would attach the vrscene file, but it errored out when I tried.

Thanks.

[james_morvay1]

I had to stop the Chaos Cloud render before I lost more credits, but the attached image is nearly exact to the output I get on my computer when rendering with progressive RTX. You can see the "blocky" spots clearly in many of the niches.

[Peter.Chaushev]

Hello, James,
There are several potential causes for the issue you illustrate.
The fastest way to assist you with it s by investigating the scene in question. If you haven't already, could you please send it over via https://support.chaos.com/hc/en-us/requests/new ?
Be sure to mention this forum thread and my name in the message box.

Kind regards,
Peter

[james_morvay1]

Hello, James,
There are several potential causes for the issue you illustrate.
The fastest way to assist you with it s by investigating the scene in question. If you haven't already, could you please send it over via https://support.chaos.com/hc/en-us/requests/new ?
Be sure to mention this forum thread and my name in the message box.

Kind regards,
Peter

I have posted a request through the link. Hopefully there is enough information there to work with

[konstantin_chaos]

Hi james_morvay1,

The issue in your project seems to be caused by the Adaptive Lights optimization.
As a temporary workaround you can try disabling the option:


I'll create a bug report for this and use your scene for testing.

Regards,
Konstantin

[james_morvay1]

Hi james_morvay1,

The issue in your project seems to be caused by the Adaptive Lights optimization.
As a temporary workaround you can try disabling the option:


I'll create a bug report for this and use your scene for testing.

Regards,
Konstantin

Thank You! Not long ago, I posted a similar issue with lighting and someone mentioned that the Adaptive Lights would take care of the issue I had, but I guess what you are saying is that the Adaptive Lights feature is suppressing Vray's ability to account for all of the lights I have? When I get a chance, I will go back into my project, disable the feature and re-render. What's odd is that I can sometimes get a different outcome, with respect to some of the niches not having that blocking effect, or I should say, it can become random in which niches get the blocking effect and which ones do not. I was concerned that it could be caused by limitations with my GPU, but it's an nvidia A4000 8gb and according to the stats in the VFB, my gpu memory wasn't maxed out.

[konstantin_chaos]

but I guess what you are saying is that the Adaptive Lights feature is suppressing Vray's ability to account for all of the lights I have?

This is correct in a sense.
The option enables V-Ray to build an internal light tree structure and then consider only a limited number of lights when evaluating the lighting for a given point.
This can help a great deal when it comes to performance and rarely leads to inaccuracies.
In your case, however, I consider the blocky artifacts a bug which should be addressed on our end.

Thank you for bringing our attention to this!

Konstantin

[james_morvay1]

This is correct in a sense.
The option enables V-Ray to build an internal light tree structure and then consider only a limited number of lights when evaluating the lighting for a given point.
This can help a great deal when it comes to performance and rarely leads to inaccuracies.
In your case, however, I consider the blocky artifacts a bug which should be addressed on our end.

Thank you for bringing our attention to this!

Konstantin

That explanation is what I have always considered for the adaptive lights, but with the large amount that I've been trying to render, I did consider at one point, in increasing the value, but held off for fear of crashing Vray and/or Sketchup. Disabling does seem like it may take longer to render, but the accuracy should be much better I suppose. Thanks again for isolating this and figuring out a workaround and you are welcome for sending this in for analysis, it was a happy accident.