AI: Pathfinding in Unity: Path

[AngryAnt]

Update 1

Added a brief tutorial to the Path documentation:

"Pathfinding in two lines": http://angryant.com/general/path/pat...g-in-two-line/


Original post

That's right! Path is back with version 2: easier to use, more powerful than before and finally available for Unity 3.x.


Pathfinding in Unity has never been easier.

• Set up waypoints in your scene using standard transform tools.
• Auto-scale and -connect with the click of a button.
• Start a path search via a single variable assigning.
• Receive pathfinding results as messages on the GameObject of origin.

Get as advanced as you need to.

• Parallel pathfinding requests.
• Custom weights based on tagging.
• Path invalidation call-back when already found pathes are rendered invalid.
• Throttle quality vs. performance at runtime.

As per usual, Path is free to use with a show-logo clause. More details in the license.


You'll find documentation available here:

http://angryant.com/path/documentation/


And a link to the asset store page plus an example seeker script here:

http://angryant.com/path/downloads/


Original blog post:

http://angryant.com/general/path/path-2-released/


Have fun!

[AngryAnt]

Added a brief tutorial to the Path documentation:

"Pathfinding in two lines": http://angryant.com/general/path/pat...g-in-two-line/

[Seon]

Looks nice and simple to use Emil... Great work. Cant wait to give it a whirl :-)

[Angstr0m]

Good work on the new Path system.

But when I try to use the path and the detonator explosion framework package in one project I get the following error:

Assets/Detonator Explosion Framework/System/Detonator.cs(366,35): error CS0117: `Resources' does not contain a definition for `Load'

This error are taken from a new project with only Detonator Framework and Path imported.

I used the actual versions of both packages from the asset store.

[AngryAnt]

Ah. Sorry about that. I see I didn't put Path in a namespace for this release. Quite silly. Will fix.

In the mean time, what you can do for fixing it is, in each file giving you that error, add the following to the top:

using Resources=UnityEngine.Resources;

Again, sorry about not wrapping this up in a namespace. I'll have a release out soon addressing this.

[legend411]

Is Path strictly a waypoint-based system, or does it have the capability to generate navmeshes?

[AngryAnt]

Path does not have built-in navmesh generation or navmesh pathfinding. Would support for pathfinding on a hand-made or elsewhere generated navmesh be of much interest?

[legend411]

Personally, I would say so, yes

My ultimate pathfinding solution would enable me to give destination move/rotation commands to AI units and have them find their own way to said destination without getting stuck, sans the limitations of raycast-based pathfinding, and with as little setup as possible

But that's probably a pipe dream, no?

[AngryAnt]

Actually no. You've got something to look forward to in the updated Path integration with UnitySteer I'm shipping with Ricardo sometime at the end of this week / start of next week.

[legend411]

Awesome! As long as there's some decent explanation on how to set it up I've looked into UnitySteer before, but gave up trying to integrate it due to documentation being virtually nonexistent.

[thcsquad]

I tried importing Path (the latest 2.02f from the Asset Store) into my project (Unity 3). The import itself seems to work, but when attaching the Navigator to any GameObject (blank or existing), the GUI doesn't show up in the inspector. There's no error messages or anything, but the only thing that appears in the inspector is the script reference itself, plus the 'Seeker Iteration Cap' setting.

When I create a new project with only Path (per the tutorial video), it does show up, so I can confirm that my download isn't corrupted or anything. Something in my project is screwing it up, but it's hard to tell what that is when there are no error messages. Could this be the namespace issue already mentioned?

[AngryAnt]

Path should not be affected by the namespace issue - it should only affect other scripts in your project. You're sure that the log is empty and that you do not have the inspector in debug mode?

I also assume you meant the "Navigation" component and not the "Navigator", right?

[hellcats]

My first reaction is that we need a way of selecting and moving waypoints directly with the mouse instead of always using the pop-up menu or the > and < buttons. One possibility would be to add temporary gameobjects as children under the Navigation game object. Then you could even multi-select and move them all at once with the built-in support in the Unity editor. These temp objects would kill themselves at game startup, or just live in an inactive layer. Otherwise, I'm liking it.

[Zyxil]

My first reaction is that we need a way of selecting and moving waypoints directly with the mouse ...

Perhaps using iTweenPath?

[thcsquad]

Yeah, I meant Navigation. Not sure why I said Navigator. And nothing indeed showed up in the Console or even the editor log. I wasn't even aware that the Inspector had a debug mode, but I turned it on and the same thing showed up, only with one private variable, Waypoints, greyed out, added.

I then thought that I should try moving the /Path/Editor folder to /Editor, replacing what was in /Editor (nothing). I succeeded in getting a bunch of Detonator errors, similar to what Angstrom was seeing. This gives me hope in thinking that perhaps Unity just wasn't seeing it in the folder before. Still no progress, though. Nothing shows up when adding a Navigation component to anything.

I might just wait until you release the new one, though, if it is indeed coming soon. I plan on integrating UnitySteer, so it sounds perfect!

[hellcats]

I just took a look at the iTweenPath editor class. He's creating a series of PositionHandles, one for each node. This would work, but it does sort of clutter the scene with lots of handles. Still, an easy solution.

[Zyxil]

Yeah, it's a bit quick and dirty, but it gets the job done. Maybe add a GizmoVisible toggle or something.

[hellcats]

It appears that Waypoint is an actual GameObject (you can duplicate one if you have it selected and get a free floating Waypoint. It also must have the HideInHierarchy attribute). So it should be a simple matter of putting a mesh on it to make it selectable.

[AngryAnt]

Waypoints are indeed components and when you create them via the inspector I set the hide flags to reduce clutter. I could make this optional if you would prefer it, but that doesn't really seem like a good fix.

I'll see what I can come up with. Thanks a lot for your feedback.

[hellcats]

Angry Ant,

I've been decompiling your code to understand it better (sorry for that). I have a couple questions:

SeekerData computes the HScore by summing the old score with the new Connections H value. Isn't this a bug? HScore should be an estimate of the remaining cost to the goal, not the sum of those estimates from the start position. Summing from the beginning is what you want for GScore, not HScore.

Also, the cost function for connections uses Euclidian distance squared. Summing those squared distances for G is not really comparable with the H value distance squared. I know doing the square root is expensive, but if G isn't computed accurately then the returned Path may not be minimal.

I don't know what algorithm you are using, so I could just be completely confused. Sorry to decompile and complain.