Assault

The purpose of an assault is to make one or more NPC(s) tactically advance along a predesigned route, securing tactical points along the way. It is much more flexible than a path_corner entity.

An assault consists of two or three component entities:

• ai_goal_assault (1 per assault, optional)
• assault_rallypoint (1 per NPC)
• assault_assaultpoint (any number)

This article will show you the overall picture on how to set up an assault. (For entity specific information, see the related entity.)

Structure

An assault consists of a an AI goal (the ai_goal_assault entity) gathering a set of one or more NPCs (called actor(s)) to one or more "rally point" locations (assault_rallypoint entities) where they will normally await a cue to commence the assault. On this cue, they will proceed to the first "assault point" location (assault_assaultpoint entity) to secure, or 'clear', clear it, and then proceed on to the next assault point (if any), clear it, and then proceed to the next, and so on. Clearing an assault point, by default, consists of standing on its location and ensuring that there are no hostiles in sight for the timeout period, but this is completely configurable.

Assaults can be triggered in one of two ways:

1. When activated, an ai_goal_assault entity can send its actor(s) to the associated assault_rallypoint(s), where they wait for the assault cue. This is the most common usage. The ai_goal_assault entity can either be activated by an Activate input, or set to start active through its Start Active keyvalue, which causes the assault to begin as soon as the map is loaded.
2. Combine soldiers may be instantly associated with a rally point without the use of an ai_goal_assault entity. Using the entity I/O system, you can fire the Assault input on the soldier, providing the name of the assault_rallypoint as an input parameter. When a Combine soldier receives this input, it will search for the specified assault_rallypoint entity, move to it, and then proceed immediately to the associated assault_assaultpoint. Please note that although the Assault input can be sent to any NPC it is only supported for Combine soldiers. You may use wildcards when specifying the rally point in the parameter. You may also use the priority keyvalue of an assault_rallypoint entity as a parameter to influence this decision, if providing a wildcard which specifies more than one assault_rallypoint entity.

Limitations and bugs

• When moving to an assault point partway through a chain, the NPC will go to the standing posture for a moment before continuing. This looks unnatural.

• NPCs will always arrive at a rally or assault point and turn to face in the direction the entity is set to. This is again unnatural in some cases.

• NPCs must stand directly on an assaultpoint to clear it without timeout if Clear on contact with enemies is not set and triggered. This can result in illogical backtracking and means that groups of NPCs moving together each need their own assaultpoint to maintain the illusion.

• A rallypoint can only serve one NPC per assault. If multiple NPCs are required to assault at the same time, each needs their own rallypoint. There may be a solution to this but it is not yet documented. Use of wildcards can make the assignment of individual NPCs to individual rallypoints easier.

• Linking an assaultpoint to a rallypoint crashes the game.

Example

This example map contains a single NPC on a linear chain using all the major options available to designers when moving NPCs from assaultpoint to assaultpoint. There are four points, and each is configured differently:

1. Clear on contact with enemies is enabled. When the NPC sees the hostiles, it clears out the assaultpoint and continues to 2.
2. Clear this point on arrival, UNCONDITIONALLY is flagged. When the NPC reaches this point it clears it regardless of the fact that there are still hostiles in sight and begins to move towards 3.
3. Allow diversion is set to No. The NPC will charge towards the assaultpoint without stopping or giving chase. It will however attack enemies in view.
4. Allow diversion is set to Yes. The NPC will divert from moving to this point until there are no hostiles visible.

Note that the Metropolice cannot harm the NPC and will not attack the player in this example.

Download Example (VMF)