Michael Booth's GDC 2004 talk on CZ bot...

[Whistler]

would someone put up a pure text version ?

That's soooooooo huge.....

[KickBot]

Great stuff thanks for sharing, it's worth the big download!
Their nav-area model looks very similar to this:
http://www.gamasutra.com/features/20020405/smith_01.htm

[Pierre-Marie Baty]

a friend of mine managed the download for me...
Nothing really new... the paper isn't really technical. I particularly enjoyed the videos, cause I never saw that bot in action before.
Good bot.
Doing better must be doable, though

[stefanhendriks]

Yes PM, thats what i thought too. I would like to see more indepth technical details

Anyway, quite impressive those 'jump marks' in those video's

[Pierre-Marie Baty]

that resembles VERY closely to what I'm doing in the current version of my bot. Although Michael made the choice to narrow the walkfaces a bit possibly for forcing the bots into a more precise navigation.

I can notice he also merges the adjacent walkfaces into larger squares, which for sure leads to much less overhead for pathfinding, but on the counterpart restricts the tactical analysis of danger points on a certain area to the corners of the square and the passage points between two areas (for example, *not all* of an open area represented by a single square is potentially dangerous - a sniper may be able to cover only a half of it).

I would have liked to see videos of bots walking on narrow ledges and difficult passages... I agree with him when he says "navigation is hell".


*edit* out of curiousity, it seems that even the storage in the .nav files is very similar... it looks like a dump of the raw corner coordinates in Vector data I think I must be able to write a tool that will convert RACC nav files into CSbot nav files and back

[KickBot]

I think he uses cells generated by a walking algorithm and then merged into areas, not navmeshes taken from the bsp file. He wrote "learning map by sampling and mergin nav area with a greedy algorithm" or something like that. That could explain why all areas are rectangular, I have seen no triangular or other polygon types in the videos or pictures. The method is described in the link I gave.
About the details well I think that for a commercial game he gave a lot of details

[botman]

I would agree. He seems to be doing a "hull test" based on the size of the player's hull. The smallest boxes all seem to be about the size of the player hull. This makes sense, since there's no reason to include little tiny triangles that the player would never be able to fit into.

botman

[stefanhendriks]

yes. I found it quite cool when he 'points' at the ground and you see those boxes on the floor. The smallest indeed around the size of a player. Very cool stuff.

I wonder if i could immitate that. Perhaps i'll just go figure that out when i have released a new version of the bot... just for the fun of it

[Pierre-Marie Baty]

hmm I would think not, due to these boxes being narrowed on all edges, even when the edge does not meet a wall (such as the top of a crate).

That hull test thing must be a pretty damn CPU intensive algorithm, elseway. Can someone tell us how long it takes for the CZ bot to pre-process a new map ?

[KickBot]

I've googled and found their forum.

Some posts have some clues, in particular this one:
http://www.turtlerockstudios.com/for...opic.php?t=260
("Mike" also explains how sniping/hiding points are found)

In other posts they mention bots ramming in tables and stuff because it's a big navarea and the bots are not aware there are obstacle in them, and you have to manually split the areas.
In another post I've seen mentionned that the nav generation find areas "outside" the playing zone of the map, so this mean they don't compute real reachability.
They also mention problems with slopes, stairs and fences.

So it seems that they really use navmeshes generated from world geometry, but have restricted the merged areas shapes to some properties like being rectangular and of enough size so a player can stand there. It is also possible to manually create and edit areas.
Also as the maps shown in the GDC videos are all standard cs maps it is possible what they show are heavily manually edited navareas that doesn't look like default generated ones.

If someone here have CZ and the tried the bots or found more infos from "Mike", that would be more reliable that our crazy speculations.