Is Vray Physically Correct?

[hereagain]

How should I set up scenes in Vray to achieve physically correct lighting conditions? I have an interior scene lit solely by daylight entering from a south facing clerestory. When compared with a rendering I did (of the same space) in Radiance and Ecotect a year ago, the Vray results don't match at all. I want to simulate as closely as possible what the human eye would perceive in the space. Any thoughts would be appreciated. Thanks.

[AJLynn]

The most "accurate" option would be to use the Vray sun/sky and the physical camera, and put your GI primary and secondary both on Light Cache, set Light Cache to Progressive Path Tracing mode and put a large number like 20,000 in the Samples slot (stopping the render when it looks reasonable). This would give you a more accurate result than Radiance.

[Christopher Nichols]

How should I set up scenes in Vray to achieve physically correct lighting conditions? I have an interior scene lit solely by daylight entering from a south facing clerestory. When compared with a rendering I did (of the same space) in Radiance and Ecotect a year ago, the Vray results don't match at all. I want to simulate as closely as possible what the human eye would perceive in the space. Any thoughts would be appreciated. Thanks.

 

You see tha is an interesting concept because what the human eye can see is somewhat subjective... I would say that even Greg Ward (the creator of radiance) would agree to that. The closest thing that a computer program can do to simulate things that are "physically accurate" is to simulate photography. Programs like Maxwell would be a good choice for that. Or, with Vray, using an unbiases system with PPT and Vray Cameras would be able to achieve that. The most interesting things I have seen to simuate human vision that Greg did was the tonal mapping stuff which shows how the human eye deals with the high dynamic range of light.

 

http://en.wikipedia.org/wiki/Tone_mapping

[ipxstudios]

where is the "Progressive Path Tracing mode" found in version 1.5

 

thanks!

[BrianKitts]

its in the Lightcache "mode" drop down menu. By default it will say "single frame", it's the last option below "from file"