Underglow and Light That Hits the Ground

A common misunderstanding: making a material glow does not make it cast light onto the road. Emissive and cast light are two separate systems in FH6.

What emissive does — and doesn't

• A colour on an emissive material only changes **what is emitted from that spot

of the mesh itself** (e.g. the glowing lens of a headlight).

• It does not light the ground, other cars, or the environment.

Editing only the modelbin/material to try to get underglow on the street will not work — this was tested directly and confirmed.

What actually casts light

To make light appear on the street you need to work with the lighting data, not just the model:

1. Add light sources to lights.bin.
2. Create your own light preset to go with them.

Both are needed together — light sources without a preset, or a preset without sources, won't give you the result.

Building an underglow bar

The mesh side of underglow is typically done by taking an existing headlight (or similar) modelbin, stripping it down to just the mesh with the glowing material, and stretching that into a bar shape. That handles the *visible* glow; the *cast* light still comes from lights.bin + a preset as above.