HDRI's for interiors... what is the correct method?

[short cirkuit]

Hi all

I have been playing around a lot with interior HDRIs and im getting mixed results.

When i use a DOME light, it adds wayyyy to much noise.... the only way i get around this is by using the HDRI in teh environment slot only with the combination of vray light portals - i kinda dont know why but this appears to work. Although the image looks good and i sholdnt complain, i would like to understand why this is so... or even if this is the right method?

Just wanting to get an insight on your methods for this particular lighting approach.

Thanks

[glorybound]

I am learning that they add realism, just a butt load of render time. Well, I guess each scene is unique, but it's not good for spaces with smaller windows.

[Svetlozar Draganov]

DomeLight usually works fine for interiors, if it is too noisy you could increase the DomeLight Subdivisions or Min Shading Rate in order clear the image.
Both approaches (Domelight and Environment + Portal Lights) are a good option for interior renders, if you have any issues with the noise clearing you may send us the scene for investigation.

[Alex_M]

I'm having a lot of troubles getting dome lights to work decently with interior scenes. They add a ton of noise even if I use light portals. This happens in basically every interior I use dome lights. Am I doing something wrong or using dome lights for interiors is not advisable? In my tests using the environment slot for lighting produces 3-4 times less noise than a dome light.

Here's a test with default vray render settings.



PS: Please switch around the text, the noisy result is with the dome light. Sorry for the mistake.

[Zdravko.Keremidchiev]

Apparently you have reversed the results in the image above.
Keep in mind that there is a known issue with VRayDomeLight and portal lights. Until we fix it we don't advise you to use this combination. You can either use the environment option or the dome light without the Portal lights.

[Alex_M]

Yes, sorry for the stupid mistake, the text should have been swapped around. The problem is that with or without portals, dome lights are still significantly noisier for interiors. Ok, I'll use the environment slots until the problem with dome+portal is fixed. Thanks for confirming the issue.

[garth100]

Oh boy. I have spent over two days trying to resolve this issue using the Dome light. I end up testing the scene with Corona and the workflow was easy with slow render time. I didn't know that the dome light not working properly until now. Nevertheless, I continue to run various test until I saw this post. I just did a test render (interior scene) using the HDRI in MAX environment map and Vray light portal. The quality was amazing I find.

I think vray should have a system in place to notify their customers of known issues and work around. I am just saying.

[Macker]

I think the reason the environment slot renders quicker is because it doesn't have importance sampling (correct me if I'm wrong)?

[glorybound]

Let me ask this. I use both the V-Ray SkyDome with HDRI and MAX's Environment slot. I do this so I can expose the sky and illumination separately. My question is, why don't I get double exposure? Does V-Ray only use one to light the scene? If there are two, it'll only use the SkyDome? I just turned off the SkyDome, using just MAX's Environment slot, and it is rendering the same as if I was using both.

[garth100]

this may seems backwards but it's the only workflow that works for me when rendering interior scenes lately. I used the HDRI in max environment and used the dome light as light portal. using the dome as light portal bring back the sharp shadows for some crazy reason. I end up loving the results. Try it and let me know how it work for you. I was watching a corona tutorial so I just copied the same workflow with the exception of the dome light as the light portal.

Skylight portal – When enabled, the light behaves as a portal or conduit for the environment behind it. With this option, the light takes its intensity and color from the environment behind it rather than from the Color and Multiplier parameters.

[glorybound]

Does the portals get its color from the VRay SkyDome (without HDRI) or the HDRI in MAX's Environment?

this may seems backwards but it's the only workflow that works for me when rendering interior scenes lately. I used the HDRI in max environment and used the dome light as light portal. using the dome as light portal bring back the sharp shadows for some crazy reason. I end up loving the results. Try it and let me know how it work for you. I was watching a corona tutorial so I just copied the same workflow with the exception of the dome light as the light portal.

Skylight portal – When enabled, the light behaves as a portal or conduit for the environment behind it. With this option, the light takes its intensity and color from the environment behind it rather than from the Color and Multiplier parameters.

[garth100]

It's from HDRI in max environment slot. I will put to gather a little tutorial when I get home this evening.

[glorybound]

It is probably getting the reflection from MAX's Environment, but I would assume it is getting the portal color from the empty SkyDome, at least that would make sense. If not, I am not sure what use the Skydome's purpose would be.

[glorybound]

It might be subtle, but I think it makes a huge difference in quality. Here is a video of me dropping my HDRI into VRay's SkyDome.

https://vimeo.com/205962410