Visleaf: Difference between revisions

Latest revision as of 17:42, 18 July 2025

A sample scene with two rooms.

The default visleaf structure for the above scene. Note how leaf 2 cannot see leaf 3.

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. visleaves 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.

Visleaves are generated automatically from the BSP tree by the VVIS compile tool. Each (internal) surface of a visleaf is either a World brush surface or a Portal to an adjacent visleaf.

Examination

There are three ways to inspect visleaves:

From Hammer Editor since Orange Box (Source 2007 and later), 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.

Tip:For even more clarity use auto visgroups to remove objects from your map that don't block visibility – i.e. everything but "World Geometry".

From the Developer Console, the console variable mat leafvis can be used. (mat_leafvis 3 will display all visleaves in the PVS.)

Note:Do not confuse visleaves with the squares outlining worldbrush geography seen if you use mat_wireframe 3.

From 3ds Max using Wall Worm Model Tools, the leaves of the current map can be viewed directly in the 3D view through the menu option Wall Worm > Wall Worm Level Design > Wall Worm Map Compile Tools > Load PRT File. This displays leaf edges that touch other edges as thick yellow lines. You can select a line (portal) that will allow you to select or flash the leaves on either side. You can also find more portal and leaf options in the Go To Brush floater.

@@ Line 1: / Line 1: @@
-A '''visleaf''', or merely a leaf, is one of many visleaves &mdash;think of them as sections&mdash; in which a map is divided during the compiling process. Each leaf is a volume that contains a section of geometry that is drawn together. When '''any''' part of a leaf is visible from the current leaf, '''all of the geometry in the leaf is considered for rendering by the engine'''. Calculating which leaves can see which is a large portion of [[|Vvis|VVIS]]' purpose.
+{{LanguageBar|Visleaf}}
+[[File:Opt_pvs_blank.jpg|thumb|A sample scene with two rooms.]]
-You can view the current leaf in the engine by typing <code>mat_leafvis 1</code> at the developer console. A red wireframe box will be drawn showing the current leaf. As you move around in the level, the box will redraw each time a new leaf is entered. Another way of visualizing visleaves is to use the [[glview]] (<code>glview.exe</code>) command-line tool.
+[[File:Opt_pvs_good.jpg|thumb|The default visleaf structure for the above scene. Note how leaf 2 cannot see leaf 3.]]
-==See also==
+{{Distinguish|VisGroup}}
-*[[Optimization (Geometry)#Visibility]]
+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. visleaves 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 [[PVS|potentially visible]] from ''any part'' of the current visleaf, the entire contents of that visleaf are considered for rendering.
-*[[Controlling Geometry Visibility and Compile Times]]
+Visleaves are generated automatically from the [[BSP|BSP tree]] by the [[vvis|VVIS]] compile tool. Each (internal) surface of a visleaf is either a [[World brush]] surface or a ''Portal'' to an adjacent visleaf.
+== Examination ==
+There are three ways to inspect visleaves:
+* From Hammer Editor since [[Orange Box (engine branch)|Orange Box]] (Source 2007 and later), 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.
+{{tip|For even more clarity use auto [[visgroup]]s to remove objects from your map that don't block visibility – i.e. everything but "World Geometry".}}
+* From the [[Developer Console]], the [[console variable]] [[mat leafvis]] can be used. (<code>mat_leafvis 3</code> will display all visleaves in the [[PVS]].)
+{{note|Do not confuse visleaves with the squares outlining worldbrush geography seen if you use <code>[[mat_wireframe]] 3</code>.}}
+* From 3ds Max using {{wallwormmtools|4}}, the leaves of the current map can be viewed directly in the 3D view through the menu option ''Wall Worm > Wall Worm Level Design > Wall Worm Map Compile Tools > Load PRT File''. This displays leaf edges that touch other edges as thick yellow lines. You can select a line (portal) that will allow you to select or flash the leaves on either side. You can also find more portal and leaf options in the ''Go To Brush'' floater.
+== See also ==
+*[[PVS]] (Potentially Visible Set): the 'cluster' of visleaves that are currently being drawn
+*[[PAS]] (Potentially Audible Set): as above, but for sound
+*[[Visibility optimization]]
+**[[Leaks]] are gaps in the BSP geometry that prevent leaf generation
+** [[Hint brush]]es tell the compiler to split leaves
+*Visleaf generation:
+** [[vvis|VVIS]] compiler.
+** [https://web.archive.org/web/20150527052701/http://rvanhoorn.ruhosting.nl:80/optimization.php?chapter=visleafs Ralph van Hoorn's explanation of visleaves].
+* [[Optimization (level design)]]
 [[Category:Level Design]]
 [[Category:Glossary]]

Visleaf: Difference between revisions

Latest revision as of 17:42, 18 July 2025

Examination

See also

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