white balance – Oded Maoz Erell's CG Log

Software:
3ds max 2017 | Maya 2018 | V-Ray 3.6

3ds max

Render a test with White Balance set to Custom with pure white color.
Let the rendering go on at least until the pixel values stabilize (the Denoiser works at least once..).

WB_A — Test done using custom white balance with pure white

set the white balance custom color to a color sampled from the VFB at a point that you know should be appearing completely neutral (neither warm or cold)

WB_B — White balance is set using sample from the test rendering

Render again.

WB_C — A new render done with the sampled white balance color

* Each time you want to test different sample locations you need to sample the pixels from the test rendered with custom pure white.

Maya

The procedure in Maya is identicle,
Add V-Ray Physical Camera attributes to the camera and enable them,
Create a test render with pure white White-Balance Color,
Sample the white/grey surface color in the V-Ray VFB (Render Window) to the White-Balance color, and render again.