Lighting

Guides

• Adding Light - A beginners tutorial on how to set up a basic light entity.
• Intermediate Lighting - A tutorial dealing with all the light sources in more detail.
• Advanced Lighting
• Constant-Linear-Quadratic Falloff - An easy-to-read explanation of the old C-L-Q light attenuation system.
• HDR - High Dynamic Range Lighting.

Entities

Static light sources

• Note: static lighting is compiled into Lightmaps (which illuminate World Brushes) and Cubemaps (which illuminate World Models).

light

A static, omni-directional Radial light source. (eg a naked light bulb or flame.)

light_spot

A static, uni-directional Radial light source. (eg most light fittings.) The conical beam angle cannot exceed 90°.

light_environment

Includes 2 light sources; a Diffuse light (eg reflected from overhead clouds/sky) and a Parallel light (eg Direct Sun or Moonlight). Both are emitted from the toolsskybox material wherever it is used on a map. See also Skybox.

env_particlelight

Illuminates only particles produced by env_smokestack. Particles are not affected by normal lighting. Use (no more than) two of these to make (only) env_smokestack particles appear to reflect ambient lighting.

Dynamic light sources

env_projectedtexture shines from a doorway.

• Note: dynamic lighting is calculated at runtime, which makes it very expensive to render.

light_dynamic

A combination point light and spotlight that can be moved, turned, and adjusted.

point_spotlight

A moveable spotlight (directional) glow, with a dynamic light source.

npc_spotlight

A spotlight NPC capable of tracking targets.

env_projectedtexture

A dynamic light that lights using a texture rather than a solid colour, and which also casts realistic dynamic shadows. Affects all surfaces that can accept lighting, and is used for the player flashlight in Episode Two.

Shadows

shadow_control

Controls dynamically projected shadows (produced by player models, NPCs, and physics props) in the entire map.

info_no_dynamic_shadow

Used to mark surfaces that shouldn't receive dynamic shadows. Useful to apply to walls and floors where shadows are drawn improperly, giving away the location of enemies.

• light_environment

Tyndall effects

Tyndall effects are caused by light scattering on suspended (colloid) particles in a transparent medium. Eg car headlights in fog.

• Halo (Glow Sprite) effects :

• env_sprite - entity used to create omni-directional glow or flare effects.
• env_lightglow - an asymmetrical glow (for areas of contrasting light).
• env_sun - adds a bright haloed spot to the Skybox to represent the position of the Sun or Moon.

• Lightbeam (Volumetric Light) effects :

• Brush texture : models/effects/vol_light001
• Brush texture : models/effects/vol_light002
• Model : models/Effects/vol_light.mdl - use with prop_static.

Common values

City 17 day

Brightness 237 218 143 800

Ambience 190 201 220 100

Ravenholm night

Brightness 175 230 239 50

Ambience 43 45 57 5

Combine lamp

Brightness 147 226 240 3000

Ambience N/A

Tungsten bulb

Brightness 254 216 146

Ambience N/A

Fluorescent bulb

Brightness 159 237 215

Ambience N/A

For values to accompany the stock skybox materials, see Sky List.

Notes

• Naming a light makes it more expensive. Only name lights when you need to. Multiple lights sharing the same name are cheaper than lights with separate names.
• light_dynamic is especially expensive, and will not even show up on some systems
• The basic light entities do not come with a visible representation (e.g. a lightbulb). For that you need a prop. See HL2 light props for a list.
• The basic light entities do not come with a "glow" as you'd expect to see in a foggy or misty area. To provide this, either compile and run the map with HDR enabled, or add a point_spotlight (with dynamic lighting off unless needed) or env_lightglow entity.
• Maps will not be lit unless you run vrad (or equivalent). Vrad will not run properly and will not calculate realistic light bounces unless the level is free of leaks.
• Several textures provide their own light & can do so using lights.rad in a mod's directory or the one in sourcesdk/bin.
• Moving brushed-based objects will not change the way they are lit. Their lighting will be calculated only according to their positions in Hammer. (e.g. a brush in a dark room will not become bright if it is brought into a bright room.)

Console commands

• mat_fullbright boolean — Toggles map lighting

See also

• HL2 light props
• Color theory (level design)
• Light entities - A list of light entities.

External links

• Understanding and Using Lightmaps - Tutorial
• Volumetric Lighting - Tutorial
• Lighting Tutorial - Covers entities & variables with examples
• Quadratic/Linear/Constant in Lights