• FEATURED

View more

View more

View more

### Image of the Day Submit

IOTD | Top Screenshots

### The latest, straight to your Inbox.

Subscribe to GameDev.net Direct to receive the latest updates and exclusive content.

# Does starcraft2 use navmesh A* or grid A* for pathfinding?

Old topic!

Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

15 replies to this topic

### #1xiongyouyi  Members

Posted 28 April 2012 - 01:27 AM

Does starcraft2 use navmesh A* or grid A* for pathfinding?

Posted 28 April 2012 - 07:55 AM

It uses a navmesh. Also please note that there is a bunch of steering code happening in there rather than simple A*.

If you want to see slides from James Anhalt's GDC presentation on SC2 pathfinding (and have some time to wait for a long PPT download), you can get them from here.

http://gameai.com/papers.php?a=23&t=&e=&y=
Dave Mark - President and Lead Designer of Intrinsic Algorithm LLC

Professional consultant on game AI, mathematical modeling, simulation modeling
Co-advisor of the GDC AI Summit
Co-founder of the AI Game Programmers Guild
Author of the book, Behavioral Mathematics for Game AI

Blogs I write:
IA News - What's happening at IA | IA on AI - AI news and notes | Post-Play'em - Observations on AI of games I play

"Reducing the world to mathematical equations!"

### #3japro  Members

Posted 28 April 2012 - 12:59 PM

Does the download work for anyone? I now downloaded it three times (two times on my windows machine and once on linux) but the zip seems to be broken .

### #4Mihai Moldovan  Members

Posted 30 April 2012 - 05:57 PM

Your question doesn't make sense.

A* is an algorithm while a Navmesh is the data structure (graph) representing your terrain. Thus SC2 uses both, A* and a Navmesh, and steering behaviour on top of that.

Anyway, I wouldn't try to learn from what Blizzard is doing with their games. They're really just not that good except for their marketing and cinematics team.

Edited by Mihai Moldovan, 30 April 2012 - 05:59 PM.

### #5Cornstalks  Members

Posted 30 April 2012 - 06:07 PM

Your question doesn't make sense.

A* is an algorithm while a Navmesh is the data structure (graph) representing your terrain.

His question makes perfect sense. He was wondering if A* was used on a *navmesh* or on a *grid*.

Anyway, I wouldn't try to learn from what Blizzard is doing with their games. They're really just not that good except for their marketing and cinematics team.

Wow... Ok...
[ I was ninja'd 71 times before I stopped counting a long time ago ] [ f.k.a. MikeTacular ] [ My Blog ] [ SWFer: Gaplessly looped MP3s in your Flash games ]

Posted 30 April 2012 - 07:48 PM

Your question doesn't make sense.

A* is an algorithm while a Navmesh is the data structure (graph) representing your terrain. Thus SC2 uses both, A* and a Navmesh, and steering behaviour on top of that.

Anyway, I wouldn't try to learn from what Blizzard is doing with their games. They're really just not that good except for their marketing and cinematics team.

You went 0-2 on this post.

1) Read the person's post before you bust out the snark.
2) You are knocking arguably one of the best game design teams in the history of ever.
Dave Mark - President and Lead Designer of Intrinsic Algorithm LLC

Professional consultant on game AI, mathematical modeling, simulation modeling
Co-advisor of the GDC AI Summit
Co-founder of the AI Game Programmers Guild
Author of the book, Behavioral Mathematics for Game AI

Blogs I write:
IA News - What's happening at IA | IA on AI - AI news and notes | Post-Play'em - Observations on AI of games I play

"Reducing the world to mathematical equations!"

### #7xiongyouyi  Members

Posted 30 April 2012 - 09:50 PM

It uses a navmesh. Also please note that there is a bunch of steering code happening in there rather than simple A*.

If you want to see slides from James Anhalt's GDC presentation on SC2 pathfinding (and have some time to wait for a long PPT download), you can get them from here.

http://gameai.com/pa...p?a=23&t=&e=&y=

The ppt zip is broken, I cann't open it.

Posted 01 May 2012 - 09:20 AM

Sigh. That's the one hosted on the GDC Vault site. Let me see if I have my own copy around here someplace.
Dave Mark - President and Lead Designer of Intrinsic Algorithm LLC

Professional consultant on game AI, mathematical modeling, simulation modeling
Co-advisor of the GDC AI Summit
Co-founder of the AI Game Programmers Guild
Author of the book, Behavioral Mathematics for Game AI

Blogs I write:
IA News - What's happening at IA | IA on AI - AI news and notes | Post-Play'em - Observations on AI of games I play

"Reducing the world to mathematical equations!"

### #9Okay Lin  Members

Posted 04 May 2012 - 01:15 AM

Sigh. That's the one hosted on the GDC Vault site. Let me see if I have my own copy around here someplace.

Could you sent me the "James Anhalt's GDC presentation on SC2 pathfinding", thank you very much
email flin0529@gmail.com

Posted 04 May 2012 - 07:04 AM

That's the one I linked to. The SC2 portion is only about 20 minutes. The rest of the hour was stuff from 2 other games.
Dave Mark - President and Lead Designer of Intrinsic Algorithm LLC

Professional consultant on game AI, mathematical modeling, simulation modeling
Co-advisor of the GDC AI Summit
Co-founder of the AI Game Programmers Guild
Author of the book, Behavioral Mathematics for Game AI

Blogs I write:
IA News - What's happening at IA | IA on AI - AI news and notes | Post-Play'em - Observations on AI of games I play

"Reducing the world to mathematical equations!"

### #11web383  Members

Posted 04 May 2012 - 02:32 PM

I'm also interested in the SC2 presentation if anyone has a valid link or copy.

### #12japro  Members

Posted 04 May 2012 - 02:43 PM

I'd also be very interested.

### #13Indakung  Members

Posted 08 May 2012 - 09:31 AM

I found that the buildings in SC2 are on grids, it seems like they combined both grid and navmesh?

I cannot open the zip too, could anybody help?

Edited by Indakung, 08 May 2012 - 07:34 PM.

### #14xiongyouyi  Members

Posted 08 May 2012 - 08:12 PM

I found that the buildings in SC2 are on grids, it seems like they combined both grid and navmesh?

I cannot open the zip too, could anybody help?

I guess, the navmesh is used for pathfinding, the grid is used for placing building, generating terrain, calculating neighbors in steering behavior

### #15Indakung  Members

Posted 08 May 2012 - 09:44 PM

I downloaded SC2, and tried its editor. Press Ctrl + Alt + H to show navMesh and put some buildings on it, it shows the dynamic generation of navMesh for the building's constructions and destructions clearly. Or you can also add polygon directly.

It's Delaunay algorithm isn't it? But my question's still: how to deal with agents in different sizes? The editor doesn't shows if it generated various layers for different size of agents.

Edited by Indakung, 08 May 2012 - 10:51 PM.

Posted 08 May 2012 - 09:58 PM

Yeah, I was going to say that the grid is just for building placement. It just gens the navmesh as needed. That's a well-documented approach for navmeshes and changeable terrain.

I looked through my AI summit files from last year and didn't see a copy of James' slides. I will ask him if he has them sitting around.

To be honest, though, the slides aren't going to tell you much.
Dave Mark - President and Lead Designer of Intrinsic Algorithm LLC

Professional consultant on game AI, mathematical modeling, simulation modeling
Co-advisor of the GDC AI Summit
Co-founder of the AI Game Programmers Guild
Author of the book, Behavioral Mathematics for Game AI

Blogs I write:
IA News - What's happening at IA | IA on AI - AI news and notes | Post-Play'em - Observations on AI of games I play

"Reducing the world to mathematical equations!"

Old topic!

Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.