Several surface flags are available in Quake2World that were not previously supported by Quake 2.
- Comparable to Quake III Arena's caulk feature; disables rendering of any face to which it is applied. Useful on backs of beams, bottoms of crates, etc.. The BSP compiler automatically assigns this flag to any surfaces textured with common/caulk.
- SURF_TRANS33 + SURF_TRANS66
- Combining the two legacy alpha blend flags causes the renderer to use the texture's alpha channel for blending. This is useful for light volumes and decals.
- Enables OpenGL alpha-test on surfaces to which it is applied, allowing for grates, foliage, railings, fences, and other textures with "holes".
- Marks surfaces for Phong Interpolation (Phong Shading) during the BSP compile process. This should only be used on curved or organic geometry such as pipes, pillars, and terrain.