PVS

A PVS or Potentially Visible Set is used as a somewhat abstract filter by NPC Sensing and the clientside Rendering Engine when deciding which parts of the World are visible to an Entity during gameplay.

A PVS is the specific set of Visleafs which are visible from a specific Visleaf; every Visleaf has it's own PVS. Each Visleaf's PVS is calculated and recorded during VVIS compiling, and cannot be changed at runtime.

An Entity's PVS (including the Player's PVS) is the PVS of whichever Visleaf the Entity is currently in. As every part of a BSP World is divided into exclusive Visleafs, any Entity will always be located in one particular Visleaf or another. If the Entity moves around the World, it will probably move from one Visleaf to another. Each time it moves to a different Visleaf, it will 'inherit' a different PVS from its current Visleaf.

A PVS test is a simple look-up to determine which Visleafs should be tested against this Entity's Viewcone.

The console variable r_lockpvs allows you to lock the PVS.

See Also

• Visleaf and Ralph van Hoorn's excellent explanation of visleafs.
• NPC_Sensing includes PVS and other vis-tests such as Viewcone and LOS tests.
• VVIS and Controlling Geometry Visibility and Compile Times.
• PAS (Potentially Audible Set).