Hi guys, This is what makes Valve's games so awesome - a superior level of details: Houndeye behaviours: https://www.youtube.com/watch?v=9jO-P3kXlCI https://www.youtube.com/watch?v=Z8_R2OMgNUY Seagull pooping at your car: https://www.youtube.com/watch?v=knSBrO3GBXY Vortigaunt raising deads: https://www.youtube.com/watch?v=RV9ooD5rx1o I don't know how much time Valve spent on modelling those :-) But that's exactly what makes their games fun! Edit: There are more details about implementation of AI: https://developer.valvesoftware.com/wiki/Category:AI https://developer.valvesoftware.com/wiki/AI_Learning:_CombineSoldier http://aigamedev.com/open/article/halflife-sdk/ Have a nice weekend, Les