Think all you have to do in Maya 2011 to work linearly is set the two input/output options in the render globals? Wrong! Well, you’ll technically be correct. But you actually have to set three other options hidden away in the preferences, otherwise your nice 32bit linear EXR files will look totally washed out.
The problem is that setting the two input/output options in the Render Globals doesn’t affect how the Render View displays images. Unless you tell it differently, the Render View will display an 8-bit file with a higher gamma, so when you texture and light your scene, you’re texturing and lighting to what looks good with the incorrect display settings. You’ll still be outputting linear files if you, say, batch render, but your lighting and texturing will be completely blown out.
When you get to a compositing program such as Nuke, you’ll quickly notice something wrong. Your first thought will be to check the viewer LUT. That’s sRGB, no problems there. Then… the file input colorspace, which Nuke automatically (and correctly) sets to linear, for an openEXR file. If you set it to sRGB, the washed out EXR magically appears correct. This is because you lit and textured it in an sRGB space, rather than linear. If you set this option in Nuke, YOU ARE THROWING OUT DATA, and might as well be rendering 8 bit files.
The solution is a tough one – relight your scene, but in the correct colorspace. This post in the Maya documentation explains tersely what you have to do:
- Set the Default Output Profile to Linear in the Render Globals (We knew this already – the input should be sRGB generally).
- Select Window > Settings/Preferences > Preferences > Rendering and select 32-bit floating-point (HDR).
- Set the framebuffer to RGBA Float 4×32 for rendering EXR’s (be sure the gamma is 1.0).
- In the Render View window, select Display > Color Management to display the ViewColorManager node. Set the Image Color Profile to Linear. This is the color profile for your image source file. (But wait! We already set the render view option, right? No! You have to set it here, too. “Image Color Profile” means the image that is fed into the Render View. This has to be linear, since we set it up in the preferences back in step 1. But we have to do set it again for some reason.).
- Set the Display Color Profile to sRGB (gamma corrected). This is the recommended option for displaying on computer monitors. (This is what ACTUALLY determines how the render view displays the image).
I’m not sure WHY steps 2-5 are not done automatically when you select “linear” in the color management section of the Render Globals, but anyway, you are now set to re-light your scene. HAVE FUN. When you get to the end, you may notice that your lights fall off more realistically. Welcome to linear space!