From Valve Developer Community
- Not to be confused with VisGroup.
Each visleaf (sometimes referred to simply as a leaf) is a hollow volume in a map which defines a 'cluster' of visible surfaces. Every visible surface of a map is part of one visleaf or another. Visleafs are used primarily by the Rendering Engine to determine (before rendering each frame) which areas of the map might need to be rendered on screen. When any part of a visleaf is potentially visible from any part of the current visleaf, the entire contents of that visleaf are considered for rendering.
There are three ways to inspect visleaves:
- From the Orange Box version of Hammer, the leaves of the current map can be viewed directly in the 3D view through the menu option Map > Load Portal File. This displays leaf edges that touch other edges as thick blue lines.
- From the desktop, the glview tool application (located in the common\[game]\bin folder) can be used.
- From the Developer Console, the console variable mat_leafvis can be used. (
mat_leafvis 3will display all visleaves in the PVS.)
- PVS (Potentially Visible Set): the 'cluster' of visleaves that are currently being drawn
- PAS (Potentially Audible Set): as above, but for sound
- Visibility optimization
- Visleaf generation: