VIS
See also: Compiling - R_Speeds -
Updated November 3, 2004

VIS is one of the compiler programs, used to compile editable maps into runnable .BSP files.

"VIS knows the brushes in the map, and the leafnodes.
Vis calculates which planes are visible from which leafnode.

"A plane can easily be built from multiple polygons, however the polygons can't reach through a leafportal (which would be similar to the surface of a hint brush, and thereby the surface of a leafnode).

"This is why using rafters that cuts in planes can be a good idea.
(Proof: http://www.egir.dk/index.php?page=vhe_rafter.htm).

"The precalculated visible surfaces to each leafnode are called leafs. The HL-engine uses these leafs to determine if a plane should be rendered from the current player position."

- Egir Helgrimson

(My thanks to Egir for this writeup. -HV)

Compile time with VIS, in some cases, can run to many hours.

There are a lot of variables that affect VIS compiling time --

Map complexity - see also Level Design

• Too many brushes can "see each other"
• Big spaces = long views
• Lots of brushes = more views
• Entity brushes (they don't block VIS)

Computer capacity

• Speed, memory, etc.

I usually compile my draft maps without VIS, because non-VIS compiling is much much faster, and usually good enough for testing.

However, when I want to release a map to the public, I take the time to run VIS (because a VIS-compiled map runs faster and smoother than a non-VIS map).

If you're not using Zoner's Half-Life Tools, use them. They are better than the standard tools shipping with Worldcraft/Hammer, offering more features and better compilation faster.