Fog

Fog gives a picture atmosphere from a depth image. The farther a pixel sits on the depth ramp, the more of the fog Color it breathes in, fading in between Start and End with an overall Density.

Cable a 3D Scene's Depth pass in, pick a colour, and the scene has weather. Animate Density and the weather rolls in. And because any grayscale image can stand in for depth, Fog doubles as a general distance-tinting tool: a gradient, a mask, a luminance pass all work.

• Aerial perspective — Distant geometry fades toward the sky colour, which is what makes a rendered landscape read as deep.
• Rolling weather — A Timeline curve on Density brings fog in and out over a performance.
• Separate the subject — Fog the background so the foreground reads clearly without moving anything.
• Colour grading by distance — A warm fog on the far plane and the picture gains depth without any blur.
• Live camera atmosphere — Depth Estimation into Depth and a webcam feed gains distance-graded haze.

• Start and End define where on the ramp the fog begins and saturates — tune them before reaching for Density.
• Pick the fog colour from the background or sky; a fog colour that does not exist elsewhere in the frame reads as a filter, not as air.
• Fog before Depth of Field: air is between the lens and the subject, so it should be blurred along with everything else.
• A Depth Adjust in front gives you precise control over which distances get any fog at all.
• For coloured light shafts rather than uniform haze, use the 3D Scene's lights and a particle cloud instead.