Window lighting

This is an ongoing list of tips and tricks I have picked up from Valve's maps and elsewhere. Feel free to add to this with anything else you feel is useful.

Window Lighting

Ever wanted to illuminate a room with outside light streaming in through the windows, but the sun's facing the wrong way? Here's a solution that Valve use commonly...

Here's your window frame.

With the nodraw texture, create a brush the same width as your wall that completely fills your window.

Texture the inward-facing side of this brush with the lights/white001_nochop texture. This is the texture that will be emitting the light.

This is all very well but not completely what we want. In this state, the light-emitting brush will be solid and visible in-game and will block leaf visibility, seeing as it is not yet a brush entity.

For the next step, tie the light-emitting brush to a func_illusionary. In the properties, set Render Mode to Don't Render.

Tip:func_brush should be used instead to conform to Valve's current mapping standards. Same properties apply.

This will ensure that the brush is invisible and doesn't collide in-game, but will cast light into the room when the map is compiled.