env_cubemapis an internal point entity available in all Source games. It specifies a location for which a cubemap will be generated when the
buildcubemapsconsole command is executed. Materials with
$envmapwill use the nearest cubemap as their reflection.
- Cubemap Size (cubemapsize)
- The resolution of each face of the cubemap. Remember that the actual number of pixels stored will be your selection times six, so higher numbers will make for very large file sizes!
¹ - To render higher resolution cubemaps than 256x256, see below.
- Brush faces (sides)
- An optional override for individual brush faces, forcing them to use this cubemap instead of one closest to them. To select faces, press the Pick button then click on them in the 3D view. Hold to toggle a face on or off.
Higher resolution cubemaps
Declaring areas for cubemaps to cover is simple, just place an env_cubemap point entity inside the space of a map. When the map is compiled with VBSP, world geometry surfaces automatically associate themselves with the nearest env_cubemap and will use the cubemap generated from it. Entities associate themselves with the env_cubemap closest to their origin (alternatively, a cubemap can be applied to specific brush faces in the cubemap's properties); moving entities will dynamically change which cubemap they use. It is important to choose env_cubemap positions properly for both aesthetic and performance issues.
Cubemaps are used in a few specific ways, and should be placed accordingly. Some cubemaps are used for reflections on static world geometry. Others are used with player entities, including NPCs. And the rest are used for any non-player reflective entities. The optimal placement of env_cubemap entities corresponds with each of these uses, to ensure the maximal benefit, visually and in performance. Here are a few simple heuristics to follow:
- If a cubemap is intended for NPCs or the player, the env_cubemap should be placed at eye-level (usually 64 hammer units) above the ground. This way, the cubemap will most accurately represent the world from the perspective of the player. You can achieve this by copy-pasting env_cubemap entities around the map floor and then use hammers "Entity Report" function to select all env_cubemaps entities and then moving them 64 units upward by using the "Transform" tool (Ctrl+M)
- If a cubemap is intended for static world geometry, the env_cubemap should be a fair distance (as a rule of thumb, 16 hammer units) away from all brush surfaces.
- A different cubemap should be taken in each area of distinct of visual contrast. A hallway with bright yellow light will need its own env_cubemap, especially if it is next to a room with low blue light. Without two env_cubemap entities, reflections and specular highlights will seem incorrect on entities and world geometry in one of the areas.
- Location changes, such as one room-to-room, room-to-outside and general location changes with great visual changes need env_cubemap entities with equal distance in both locations to the transition point. For example 16 units away from the doorway into each rooms. That way the cubemap transition between locations is smooth. This will prevent the cubemap from showing the outside location inside the room and vice versa.
For general and game specific information about building cubemaps, visit the Cubemaps Page