How can I use an HDRI environment proxy to light a 3D asset in a scene?

Hugues replies As part of an ongoing project, I am faced with the arduous task of lighting a scene with multiple characters. I want the lighting to be as accurate and rich as possible, but I also want it to be coming entirely from the physical environment that surrounds my subjects. The environment is my light rig.

The creation process for such a precise approach takes a lot of tweaking. It is a heavy procedure. In order to simplify this process, allow for a more flexible workflow and faster iteration speed, I worked on the environment separately by using an HDR environment proxy.

I created a very simplified version of my environment that I could rapidly iterate on – in this example, a simple room with an open doorway and two windows that I can very easily modify, or bring into Mudbox or ZBrush, to sculpt or paint walls and rough details. I then render a panoramic image of the environment and save it in HDR format. Now I use this image to light the scene containing my characters.

This means I can now go back to my environment and increase the detail where needed or add more models to the scene, adjust the sun direction and re-render the panoramic proxy until I am satisfied with the overall depth of illumination. It greatly accelerates the rendering time of the final subjects, and allows for photo manipulation on the environment probe itself in Photoshop to adjust light intensity, gamma and global or local colour grading.