Show dust floating in a beam of light, glowing only inside the beam

Dust hanging in a shaft of light through a boarded window is a quiet, strong picture, but dust drawn all over the room looks like noise, and dust that wraps at the edge visibly pops. Here is how to make the specks light up only where the beam falls and slip in and out unseen.

Why this works

Dust is always in the air, but you only see what the light hits. So brightness comes from how close a speck is to the beam, and fading it at the room's edge hides the moment it wraps around.

When not to use it

Don't use it in a bright, flat-lit scene or a fast action game, where the beam and the specks are never seen long enough to matter. A single soft haze image is cheaper and looks as good.

In the full entry

• What to build, step by step
• Starting values and the reason for each
• 3 common mistakes and the fix
• 37 lines of example code with 4 checks that pass
• How your AI shows you that it works

Say this to your AI

Use the Spielerando entry "Show dust floating in a beam of light, glowing only inside the beam" (read_entry dust-motes-visible-only-in-the-light-beam) in my game. Build it step by step, and show me how you checked that it works.

Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP