Enemy AI

PREMISE

Enemy AI in Half-Life is much more advanced than in most previous first person shooters, it uses a series of info_node's to help the enemies move around the map better. In this tutorial, I'm going to try and show you how to use these nodes to make a level more challenging without adding any more monsters.

WHAT IS AN INFO_NODE?

Info_node's are points that help enemies navigate around the map. If they are used well, even the best players should not be able to escape from following enemies.

BASIC USE

The most basic way to use an info_node is to place it so that it is centered on the ground (although this isn't required, I recommened it) and placed where you want monsters to go. Here is an example of a map that uses info_nodes (the info_node's show up in yellow).

Map using info_node's

CORNERING

Something that many mappers mess up on is cornering with nodes, when cornering, you will want to place 3 nodes around the corner so the monster has time to turn before going all the ways around the corner.

Use 3 nodes around corners

ADVANCED USE

A more advanced way that you can use info_node's (usually in conjuction with infodecals) is to set the "hinttype" and "activity" keys to make monsters do various things at that node.

Node Properties

MISC.

Nodes, as with many things, have some limitations, one of which is that one node can only see up to 128 other nodes. Also, when using assassins, use lots of nodes to help them move better. Lastly, remember to not place nodes roughly 24 units from any brushes, as the node will not fit and will show up like red sparkles circling more red sparkles (if you see it, you'll know what I mean...).

Quakeguru