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A cubemap example containing the white static prop car, a sprite and decals. Note that the blue physics prop car is not visible in the cubemap because it is not static.
Env cubemap.png

env_cubemap is a internal point entity available in all Source games. It specifies a location for which a cubemap will be generated when the buildcubemaps console command is executed. Materials with $envmap will use the nearest cubemap as their reflection.

Note.png Note: This is an internal entity. When the map is compiled by VBSP it is processed and then removed: it does not exist when the map is running.
Note.png Note: Cubemaps will contain static props, sprites and decals, such as enemy blood and user sprays.


Comparison of reflection quality. 1x1 is not included because it does not reflect at all.
Cubemap Size (cubemapsize) <choices>
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!
  • 0: Default (usually 32x32, depending on the game)
  • 1: 1x1
  • 2: 2x2
  • 3: 4x4
  • 4: 8x8
  • 5: 16x16
  • 6: 32x32
  • 7: 64x64
  • 8: 128x128
  • 9: 256x256
  • 10: 512x512 ¹ !FGD
  • 11: 1024x1024 ¹ !FGD
  • 12: 2048x2048 ¹ !FGD

¹ - To render higher resolution cubemaps than 256x256, see below.

Brush faces (sides) <sidelist>
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 Ctrl to toggle a face on or off.

Higher Resolution Cubemaps


Turn off Smart Edit and type in a value 10 or more. That will give the resolution corresponding to the next powers of 2 (512x512, 1024x1024 etc).

Warning.png Warning: In Counter-Strike: Global Offensive trying to build a 1024x1024 cubemap will result in Engine Error.
Note.png Note: Building cubemaps requires your screen to be at least 4 times in each dimension as big as the cubemap's resolution. If your screen is smaller than that, use Dynamic Super Resolution (DSR) to build them.
Note.png Note: Having high resolution cubemaps can significantly increase the map file size. So use sparingly for things like mirrors and marble surfaces, if you're concerned about file size / client download time for multiplayer maps at least.


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.
Tip.png Tip: You can achieve this by copy-pasting env_cubemap entities around the map floor and then use Hammer's Entity Report function to select all env_cubemap 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 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.

Building Cubemaps

For general and game specific information about building cubemaps, visit the Cubemaps page.

See Also