VRay Render Output Levels

[tmccarter]

I have a question regarding VRay output levels. When I render my scene (vray advanced 1.47) consistently I have to adjust the levels in AfterFX to give the image proper gamma and white levels. The images below show before and after the adjustment. My color mapping is exponential with bright multiplier of 1.5 and a dark multiplier of 2.5. Any suggestions on how to get proper levels from VRay so we don't have to adjust them in post? Thanks in advance.

[Wayne Harney]

Your best bet is to work linearly. These 2 articles will get you started. It's a lot to digest but is well worth it.

http://throb.net/site_main/LinearWorkflow.html

http://www.gijsdezwart.nl (click tutorials)

In addition to this workflow you can also work in HDR. Save your renderings to vrimg format (option in the vray vfb) and use the vrimge2exr conversion utility to extract EXRs (similar to HDRI but uses lossless compression for much smaller files). You can also extract g-buffers and EXRs will open in PS cs2 (you can adjust gamma and exposure!) and they work well in after effects from what I've heard.

http://www.spot3d.com/vray/help/VRayHelp150beta/tools/vrimg2exr_14703.rar

http://www.spot3d.com/vray/help/VRayHelp150beta/tools_vrimg2exr.htm

Splutterfish has a free EXR importer for 3dsmax.

[tmccarter]

Thanks for the reply. Very interesting information. We did the recommended corrections for our workstations and it of course improved the way we viewed the final image, but when we open the resulting tif file in photoshop, there was no change in the rendered image. The problem is that our client is complaining about the rendered image looking too dark, and by correcting our displays, we would only worsen the problem (because we would have a tendency to make the image even darker). How do we get our rendered image file to look like it does in our workspace? Thank you again.

[jkletzien]

Is your client commenting on the images on their screen or coming to your office and commenting on your screen?

 

My own sense is that it isn't a VRay question, it is that your sky is too dark and it is visually pressing down on the buildings. The shadows you have on your buildings (soft and light), would not be produced by the kind of sky you're using, and your client intuitively is sensing that - even if they can't find the words to express it.

 

If the shadows are light, and the highlight areas still show a diffuse color (instead of being blown out) than probably it is a overcast or very humid day - so light diffuses into the nooks and crannies, and is filtered to not burn things out -but the sky won't be azure blue (aka no humidity).

 

I would brighten the sky (and mountains) a lot.

[Sawyer]

The easy linear is the change color mapping to gamma and have the multipliers at 1 & .4545 (l/d). That will burn the linear curve into the final image.