"A Spy Game About Subtle Behavior" and "A Puzzle Game About Observing People": Spy Party and Remote Shepherd

I'm reading this month's issue of GameInformer, and there's an interview with some guy named Chris Hecker. Some of you may have heard of him. Anyways, he's talking about this game he's working on, Spy Party. As I'm reading about this game where one player tries to blend in with a crowd of NPCs, and another with a sniper rifle tries to identify that player via behavioral cues, I think to myself: this sounds familiar.

Oh right, I just finished making a single player version of this game.

The World Is Not A Round, Spherical Place: Nav Meshes vs. Path Nodes

First printed as "The World Is Not A Round, Spherical Place" on the Remote Shepherd Dev' Blog


AI characters need a way to get around the world, and we considered three ways to let them do this. The first was local avoidance, but this can very easily devolve into dithering unless the level is specifically designed to prevent it. As such we decided to do actual path finding, the only decision left being whether to use a node graph or a navigation mesh. We decided to go with a navigation mesh based on the recommendations of this article. I'll summarize the relevant points here.

Spinning Class - FSMs versus Behavior Trees

Being the sole AI guy on my capstone project (Remote Shepherd) has had me buried in finite state machines and behavior trees for the past 17 weeks. Obviously there are differences in the two approaches, both have pros and cons, but as I was working out the behaviors of a particular NPC for Remote Shepherd (specifically, the Mob Agent) I came across something interesting and useful: the differences in the way each implementation handles spinning on a behavior. The short version is that when an FSM spins on a state it only cares about that single state, when a behavior tree spins on a node it still checks the relevance functions of every node with higher priority. For the long version I'll start with describing the behavior I was trying to model that led to this realization.