AI Wander Behavior

This article is for CRYENGINE 3.4 or earlier. The Behavior Selection Tree and old-style behavior scripts was deprecated in favor of the Modular Behavior Tree in CRYENGINE 3.5 and beyond.

Overview

This tutorial is a simple implementation of wander behavior.

Attachments

Please use the following attachments to this document:

Creating AI Wander Behavior

1. Add the Walker.xml file to the following folder:

Game/Scripts/AI/SelectionTrees

2. Add the WalkerIdle.lua script to the following folder:

Game/Scripts/AI/Behaviors/Personalities/Walker/WalkerIdle.lua

3. Start the Sandbox Editor and open or create a test level. If the Editor was already active, on the menu bar, go to the Tools menu and select Reload Scripts.

5. Insert a Grunt entity into your level.

6. On the Entity Properties tab, set the BehaviorSelectionTree property to "Walker".

7. Make as many copies of him as you want.

8. Click the AI/Physics button at the bottom of the Perspective Viewport.

Debugging

The following debug options may be helpful:

ai_DebugDraw

 
Toggles the AI debugging view. 
Usage: ai_DebugDraw [-1/0/1] 
Default is 0 (minimal), value -1 will draw nothing, value 1 displays AI rays and targets
 and enables the view for other AI debugging tools.

ai_DrawPath
DUMPTODISK

Draws the generated paths of the AI agents. ai_drawoffset is used.
Usage: ai_DrawPath [name]
none - off (default)
squad - squadmates
enemy - all the enemies
all - all AIs

ai_StatsTarget

 
Focus debugging information on a specific AI 
Display current goal pipe, current goal, subpipes and agentstats information for the selected AI agent.
 Long green line will represent the AI forward direction (game forward). 
Long red/blue (if AI firing on/off) line will represent the AI view direction. 
Usage: ai_StatsTarget AIName 
Default is 'none'. AIName is the name of the AI 
on which to focus.

ai_DrawRefPoints

 
Toggles reference points and beacon view for debugging AI. 
Usage: ai_DrawRefPoints [0|all|name] 
Default is 0 (off). Indicates the AI reference points by drawing 
cyan balls at their positions.

Further Notes

Note that the WalkerIdle.lua script relies on the ACT_GOTO convenience method, which uses blocking "stick" goalop. Using the non-blocking "stick" goalop with different parameters can yield other, more sophisticated behaviors.