Glossary

Glossary

Term	Meaning
block	Everything that has been marked, considered as a unit.
current (point/line/side/segment/object)	The selected point/line/side/segment/object.
Descent, Descent 1 (D1)	The first of the games in the Descent trilogy, released in 1995. DLE.NET is capable of creating and editing Descent 1 levels.
Descent 2 (D2)	The second of the games in the Descent trilogy, released in 1996 as a sequel to Descent. Internally, Descent 1 and 2 use very similar engines, and thus levels created in one are relatively easy to port to another. In terms of level design, Descent 2 adds its own set of robots, completely revamps the trigger system, introduces per-level palettes, increases level restrictions, has a different set of textures and adds support for per-level texture and robot modifications.
Descent 2: Vertigo (Vertigo)	A Descent 2 add-on that includes a new 20-level set and adds new robot types.
D2X-XL ("XL")	A source port capable of playing Descent 1 and 2 levels, which also adds its own level format with new features, like triangular segments, effects, colored lighting, new trigger types, and significantly increased level restrictions. D2X-XL enhanced levels can only be played in D2X-XL. XL levels are mostly fundamentally Descent 2 levels, and thus will allow the use of all Descent 2 features; however, XL also supports some extra features in Descent 1 levels.
Descent 3 (D3)	The third of the games in the Descent trilogy, released in 1999 and using a completely different engine. DLE does not support Descent 3 levels.
DLE-XP	Based on Descent Mission Builder 2 (DMB2), an official Descent 2 level editor released with some add-on packs, DLE-XP (Descent Level Editor XP) is a third-party Descent level editor that is the direct ancestor of DLE.NET and was the first to support extra D2X-XL features.
door	A special type of wall that can be opened, usually temporarily. Doors are most often, but not necessarily, opened by a player touching it or hitting it with a projectile. Doors may require a key from the player trying to open them, and are practically always technically two walls, as they expect to be present on both sides of a segment-segment connection.
effect	A D2X-XL exclusive object type that serves as a decoration.
energy center, fuel center	A special type of segment that will refill the player's energy (required for firing most weapons) to 100 while the player is within it. A player can use an energy center for an unlimited number of times.
exit	A special trigger type that is used to end the level. Most often attached to an exit door that is locked until the reactor has been blown up, but there is little technical restriction against placing an exit trigger without any reactors or bosses.
.HOG	The file extension used for archives containing levels and other data. Missions usually consist of a .HOG and a mission data file (.MSN or .MN2).
key	A special power-up that is required to be collected in order to open key doors. Used in Descent 1 and 2 levels to require the players to explore the mines in order to progress. Keys are not consumed and the player will keep them for the rest of the level, even on death.
line (edge)	One of the twelve edges in a segment that connects between two points in that segment.
marking (tagging)	Points can be marked, which highlights them in the mine view and makes edits acting on marked points act on them. Lines, sides and segments can also all be marked by marking all of the points they consist of, and are respectively affected by actions acting on whatever is marked.
mine, level	A single playable level in Descent 1 or 2.
mission	A set of levels, secret levels, briefings (text) and other data intended to be played in its complete form. Includes its own metadata, like a mission name, list of levels, version and author information, as a part of a .MSN or .MN2 file.
.MN2	The file extension used to store mission data for a Descent 2 mission. Has a plain-text format.
.MSN	The file extension used to store mission data for a Descent 1 mission. Has a plain-text format.
object	Objects have various roles, including the player ship itself (the starting point is placed in the level editor), robots, powerups and more. They are associated with a position in the level, much like points would, but also with a specific segment (which must match in their position within the mine).
other segment	A second selected segment which is used with various actions, such as joining/separating points/lines/sides and exchanging the current selection with the "other" selection. The other segment will, like the currently selected segment, also have a selected side, line and point.
Overload	A spiritual successor to the Descent games developed by many of the same people as the original games and released in 2018. While the Overload engine is a lot more modern, the level formats share similar core concepts and it is thus possible to convert (the geometry) of Descent levels to Overload levels, a feature supported by DLE.NET.
.PIG	The file extension used to store textures, palettes and other game data for both Descent 1 and 2.
.POG	The file extension used to store custom textures for Descent 2 levels.
point	A segment consists of eight points, all of which have independent coordinates.
pyramid	A special segment that has the shape of a pyramid instead of the standard hexahedron/cube. Only supported in D2X-XL levels.
.RDL	The file extension used with Descent 1 levels. Presumably stands for "Raw Descent Level", as the internal level format used by the game (and automatically compiled from the .RDL) is considerably different.
reactor	A special type of object, of which there should be only one in a level. The objective in most Descent levels is to reach and destroy the reactor, after which a level countdown will begin and the player must reach the exit before they run out of time. In some levels, a reactor is instead replaced with a boss robot. A reactor can have ten targets each pointing to one side of a segment, and once the reactor is destroyed, any doors referenced by such will be opened.
.RL2	The file extension used with Descent 2 (including Vertigo and XL) levels.
robot maker, bot maker, materialization center (mat cen)	A special type of segment that can be activated, resulting in 3-6 (depending on difficulty) robots spawning to the center of the segment, one at a time. On most difficulties, robot makers can only be activated three times, after which they will no longer activate.
segment (cube)	A Descent 1 or 2 level consists of segments, which are geometrically strictly convex hexahedra (in layman's terms, a cube that can be distorted in any way possible, as long its own sides neither intersect each other nor are on the same plane as each other). A segment consists of 6 sides, 12 lines and 8 points, and every mine must contain at least one segment. If a segment is connected to another, it is a neighboring segment of that segment.
selection	At any one time, it is possible to select one segment at a time, of which one side can be selected at a time, of which one line can be selected at a time, of which one point can be selected at a time. The degree of selection is controlled by the active selection mode; see it for more information about the selection system. Most actions will by default affect only the selection. The selected segment is also called the current segment, the selected side the current side, etc.
side (face)	Any of the six sides of a segment, which may be each connected to another segment. A side is closed if it is not connected to another segment, or open if it is. Only closed sides and sides with walls may have textures.
trigger	In D1 and D2, a standard trigger, which is attached to and associated with a wall that activates either when a player flies through the wall or if the attached monitor/control panel is destroyed. When triggered, they perform actions like activating robot makers or opening doors or walls. A trigger can have at most ten targets, which are all one side of a segment. In D2X-XL, triggers may also be attached to objects and thus be object triggers, activating when a power-up is collected, a robot is destroyed, or upon some other behavior. XL triggers can also have more metatrigger behavior, such as activating, disabling or enabling other triggers. XL also makes it possible to have objects as trigger targets.
unit	The unit used in all coordinates in Descent levels. The standard segment is 20x20x20 units, while the player hitbox is approximately 10 units wide. A decent-sized level is usually around 800-1200 units long on its longest axis. The bounds of the game are at around 32000 units in both directions.
vertex	A point (in the diagnostics tab), such that two joined points are considered a single vertex. The current vertex index is also shown in the status bar.
wall	Attached to a single side of a single segment, walls usually represent doors, open walls (for triggers), fans/grates or control panels/monitors.
wedge	A special segment that has the shape of a triangular prism instead of the standard hexahedron/cube. Only supported in D2X-XL levels.