This guide will usually not explain the meaning of common keyvalues, such as - but not restricted to - "targetname", "target" and "angles". Henceforth, here is a short guide to the most basic of keyvalues, assuming you already have read about Entity rendering
, so I need not explain any of the rendering-related keyvalues here anymore.
Explanation of common keyvalues:
- "Name", targetname :
- This always means an identifier for the entity in question. If you name a door "douchebag" and have a button targeting "douchebag", that door will move as you push said button. Of course, naming a door "douchebag" is ill-advised, as it would not help you keep track of what the entities in your map represent and do. Many entities need no name, or behave differently depending on whether they have one or not.
- "Target", target :
- This always is a field to put in the name of an entity. Which function relates to it depends on the respective entity. Most will just trigger their target, while others will perform actions on their target or use it as a reference for other activities. Often, multiple entities by the same name may be targeted. Most entities need no target, but having one is essential for most logic entities and basic trigger-systems.
- "Pitch Yaw Roll (X Y Z)", angles :
- Where Z means Y and Y means Z, that is, when you're thinking Hammer-grid. (Hammer uses Z for height and Y for depth, while every other sane 3D-application does this the other way round; nonetheless this keyvalue description has the letters in the conventional order) This, technically, is a 3D-vector containing Euler-angles to describe either the entity's rotation or direction of effect. E.g. a func_door_rotating will use this as its initial rotation, while a trigger_push will keep its original alignment and use this for the direction of its push-effect instead. Euler-angles are a hierarchical system to determine an object's orientation in 3D-space. A yaw-value of 0 would mean the entity would face east. (right in top-down view) 90 would mean it would face north. (up in top-down-view) After yaw, pitch is applied. Think aiming up/down with your character in first person. At last, the roll-value is applied. Think your character falling over sideways in first person. Some entities, mostly point entities, do not use the angles keyvalue for any purpose.
- "KillTarget", killtarget :
- Same as target, except that this supposedly causes the specified entity/entities to be removed from the game. Not all entities which have a target to trigger will also handle killtarget. You may want to use a trigger_relay to make sure it is working.