2D NavMesh PathFinding......

Hey there. Thank you for this package. Its been a great help so far. But i still ran into a problem and am wondering if you might help me out with it.
Im making a topdown game (zelda perspective) and generate some areas via code and bake the navmesh etc and everything is working nicely. i add placeable objects that carve themselves out of the navmesh and thats working nicely as well. now i was experimenting with agent radius for npcs and with voxelsize.
lets assume i have a narrow corridor where there is one tile floor and to the left and right side a wall. when im using agent radius of 0.5 then the navmesh doesnt get generated. i made it a little smaller, and tried 0.49 (because maybe rounding problems or whatever) but the same. i ended up taking 0.33 and that seems to work quite good when i leave the voxel size at the standard 3x radius.
now to the problem... when i make narrow corridors and have a corner leading into those (or maybe other corners as well but here is where i noticed it the most) then the agent will run to the side of the corner, moves towards the corner, sliding along the side and getting slower and slower and then when he is very close to the edge he stops and cant move away. ill add an example.
i tried changing the voxelsize to a super slow 33x radius but its still the same. when i change the radius of the agent down to something like 0.1 then the problem disappears, but obviously the npcs start clipping through everything.
they have a circle collider with 0.33 radius, the same as the setting in the obstacle avoidance but the collision is turned off. i changed the obstacle avoidance to none because otherwise the npcs would block each other indoors but its unchanged. i even get the feeling that when turning obstacle avoidance on the problem is better.
this happens especially on corner but sometimes, when he gets a waypoint outside of the navmesh, he does the same on a straight wall.
im kinda lost on how to fix this...

here is a screenshot of the navmesh agents gizmos. the corner is made up of carved out objects, placed by me during runtime. i tried setting down the carving size a bit but that doesnt change anything.

edit: i experimented around a bit more and it seems that the problem is mainly when having objects that carve out the navmesh close to another. e.g. i make a wall with chests that have a carve out value of x,y (1,1), so one tile sized and make a wall with them forming a corner. and its not on all corners as well. ive been trying different things and when i reduce the carve out size to 0.95, 0.95 then it works as well but im getting closer to the wall and the clipping starts again. gonna try this again after the long weekend. but if you got any idea what i should look at, that would be very helpful. thanks!

 

@unity_XcvZUzrkJ7ji7Q,

Hello. Thanks for describing the issue.

I also encountered issues you described. Like agent radius 0.35 doesn't get mesh for corridors that are 0.75 units. So I just changed game design to accommodate that, as I'm not able to produce better solution than Unity's navigation system in given time constraint.

But, I didn't encounter agent cornering issue, as I thought Unity's agent are very janky, so wrote my own with help of static member functions in NavMesh class (that also janky, but enough to move along the project).

From image I see, on that corner you have 5 or 6 very narrow navmesh 'tiles' on 1 side, it can be the issue with the cornering. You can look up Unity's issues on pathing through to many tiles, I believe workaround is path splitting, but its only a guess.

Also you can try to scale your game, so you will not get values bellow 1 in navmesh, it also can help.

And finally, try out https://arongranberg.com/astar/features especially functions like:

1) Grid Graphs
2) 2D Pathfinding

https://arongranberg.com/astar/freevspro it seems those features are free

 

I have been playing around with this a little bit more and have been drawing corner points for the path to see how he is moving and he walks straight up to the edge and turns and continues. the amount of cells arent really the problem cos even with just 2 or 3 navmesh cells he slows down until basically standing.

then i tried a different approach and was making a bezier curve out of the edges to test if it works better. but the problem is i cant figure out how to make the navmesh agent utilize the new points.

the logic is basically the following:
- if the path has more 3 or more corners i take the corner points of the calculated path of the navmesh agent and put them in an array
- i calculate a bezier curve between the first 3 points to make it extruding and fitting around the corners.
- i visualize the new points via gizmos and it looks good.
- next i found out that i cant just set the corners of the path so i tried different things:
1. i tried to change the corner points of the path directly, as was suggested in another thread about the topic. but thats not working anymore (at least not for me). i can set the points and dont receive any errors but when i check the points directly after setting them (one line later) then the point didnt change at all, no matter if changing the whole vector or just x or y of it.
2. i tried making a new navmesh path, calculated a path for the destination of the current path, set the corner points to the bezier list points and when i check those the points of the path and the list are identical but as soon as i want to set the current path to the new path either with agent.path = newpath or with agent.setpath(newpath) nothing happens. it returns true but the corner points are exactly the same as before.

note: i have auto-repathing turned off for testing and it didnt change a thing. when resetting the path without reassigning it to the new one the path is empty, so it doesnt get recalculated / assigned from somewhere else.

is there really no way for the navmesh agent to get a custom path somehow, even if i already have a path with correct values? i assume when assigning a path the navmesh agent somehow checks the new path and just overrides the values with "better" ones... which would make assigning custom paths impossible with unitys navmesh agent.

i guess i have to write a custom movement agent now?

 

oh btw i remember trying to get the aron granbergs pathfinding to work with your navmesh but that didnt really work out well and i was having trouble setting up links between grids for npc teleportation purposes via runtime and after testing your navmesh stuff everything was so easy that i never looked back

 

@unity_XcvZUzrkJ7ji7Q,

I don't have answer to you. Writing custom Agent is a bit of a challenge.
But if Unity Agent doesn't work for you, it worth a try.

And back to "aron granbergs pathfinding", you may try to adapt his agent to your needs.

 

Hi @vhman, sorry I have to ask you again.
So in my project the AI looks fine, even when I'm changing the agent by code.

But there's a problem when I'm trying to implement a new behaviour for a new AI.
I have a custom bake surface for a specific agent type, so I set the agent type for the new AI, but the AI does not show when I'm playing the scene. But the AI show just fine when I'm using the humanoid agent type.

So I decided to try it in a new project, but the AI not showing even though it's humanoid.

Any ideas?

 

Here I give the screenshot.
The circle NPC is not "behind" the tilemap, it's somehow hidden.

 

Ok, so it's a stupid problem.
I forgot to put the code required in the "start" method (updateRotation, etc.).

So yeah, it's solved. Sorry if I'm just flooding the thread with a stupid question lol.

 

Hi there @vhman , I have this weird issue when using the h8man/NavMeshPlus. The github pointed here to discuss, so I was wondering if anyone else had this issue. When setting the position around a corner/near a corner, the agent gets stuck and moves very slowly to the destination. I am not doing anything complicated or hard in code, just where the player clicks, set destination of the navmesh to there.

Here's a gif as an example:

https://i.imgur.com/QO8bOR1.gif

And another one. The white line is from the agent to the end point

https://i.imgur.com/m1teWHs.gif

 

@CNibbles, Hello.

Nope, you are not the only one. Few posts up, also the same issue. I think I saw this issue in general discussions on NavMesh.AI

I never had this issue, so I have no idea why it happens. Also, NevMeshPlus is only proxy to bake the mesh, afterward its unity job.

@unity_XcvZUzrkJ7ji7Q, did you solve your issue?

With quick googling I found few possible workarounds:

https://www.reddit.com/r/Unity3D/comments/4rgmm6/why_does_my_nav_mesh_agent_slow_down_around_the/

SOLVED - If I turn the Obstacle Avoidance Quality to None, it seems to just perfectly follow the path.

https://forum.unity.com/threads/nav-mesh-agent-slow-down-in-the-corners-overlap.570754/

- If I use obstacle avoidance : Quality : None
Speed in the corners is no longer decreases

https://issuetracker.unity3d.com/is...ing-a-small-gap-when-using-obstacle-avoidance

 

It is strange. I've tried to debug it for a few hours, but everything in terms of the agent movement/paths seems normal. I've also noticed the agent's Z moves ever so slightly with the Y, so it could be just a side effect of the proxy you've made. If I figure out a fix, I'll post it here

 

Hey!
Could you explain how to build at runtime?

 

Hi,

There currently no tutorial on runtime bake. But you can experiment for your self

with scenes:

https://github.com/h8man/RedHotSweetPepper/tree/master/Assets/Scenes/SampleSceneRuntime
https://github.com/Unity-Technologies/NavMeshComponents/tree/master/Assets/Examples/Scenes

and scripts:

https://github.com/h8man/RedHotSweetPepper/blob/master/Assets/Scripts/RuntimeBake.cs

 

@KlaudiaMK,

I just looked into the code and documentation, and found that you need to call a single method to bake at runtime
This method, you can call it on Start(), or if you prefer colliders on LateUpdate()

Code (CSharp):

1. public AsyncOperation BuildNavMeshAsync()

(see notes https://github.com/h8man/NavMeshPlus/wiki/HOW-TO#use-geometry)

And if you need update use this one:

Code (CSharp):

1.         public AsyncOperation UpdateNavMesh(NavMeshData data)

but it does not cache sources, so you might use its internal method

Code (CSharp):

1.  NavMeshBuilder.UpdateNavMeshDataAsync(data, GetBuildSettings(), sources, sourcesBounds);

hope it helps

 

@KlaudiaMK,

New wiki page added:

https://github.com/h8man/NavMeshPlus/wiki/HOW-TO#bake-at-runtime

 

Unable to bake nav mesh. Tried clearing nav mesh and baking too, to no avail. Getting a null from the inspector for the nav mesh data.

 

@nubbyninja , Hi!

I don't how it can happen, cause builder does check tile node before getting any info to avoid nulls.
Anyway, I add second check that will fix this particular exception, so download new sources from github.

Thank you for feedback!

 

Thank you! Will try it out momentarily.

 

Hi, I can't seem to find much info, but will this generate on the top of 2D platforms? (Like oldschool Mario Brothers)
So basically identical to the current navmesh, but able to generate on top of 2D sprites instead of 3D blocks.

Or is it only meant to generate as a floor around other objects, like for top-down games?

 

Hello @Juice-Tin

This component is made toward top-down games, and doesn't support platformers.

 

Hello, Thank you for fantastic Navmesh plus.

I have a problem that need some help. I tried to program my AI to find the closest target by checking if the target if available and calculate the distance between target and the AI.

The problem is that Navmesh.CalculatePath always return invalid for unknown reason while setDestination is working totally fine.

I tried fix it for a while and got it to work afterI bake NavMesh again but after that when the first target disappear or the AI teleport from enemy it stops working CalculatePath always return false again.

 

@Kae-am,

It is not well documented, at least not in explicit way, but you must supply NavMeshQueryFilter all data, including cost.
Or, if you want to simply check "is there a path?" use NavMesh.CalculatePath(transform.position, target.position, NavMesh.AllAreas, path);

1) Verify that you are using NavMesh.AllAreas
2) Make sure that points are on a mavmesh plain. (z equals 0)

Unfortunately I lost my working example, but if you still would have any troubles, leave a message, I will try to help you.

 

Thank you a lot! Everything is working correctly now. I will let you know if I run into any problem in the future. Your addon is fantastic!

 

Hi - currently using NavMeshPlus, I have an issue where the enemy stops chasing, or at least starts moving super slow. I build the navmesh fine, and the test AI code is as follows. Anything obvious amiss in the code? I can also send you a test project if you have time to take a look at the issue.

Code (CSharp):

1.  
2. using UnityEngine;
3. using UnityEngine.AI;
4.  
5. public class SimpleAI : MonoBehaviour
6. {
7.     [Header("Movement Settings")]
8.     [SerializeField] float moveSpeed = 1f;
9.     [SerializeField] float maxMoveSpeed = 1.5f;
10.     [SerializeField] float chaseMultiplier = 2f;
11.  
12.     [Header("Distance Settings")]
13.     [SerializeField] float viewDistance = 7.5f;
14.     [SerializeField] float minDistance = 0.5f;
15.     [SerializeField] float attackDistance = 1.5f;
16.  
17.     private NavMeshAgent m_navMeshAgent;
18.     private Transform playerTarget;
19.     private Vector2 playerPos;
20.     private Vector2 targetPos;
21.     private Vector2 relativePos;
22.     private Vector2 relativeTargetPos;
23.     private float distance;
24.     float finalMoveSpeed;
25.  
26.     void Start()
27.     {
28.         // Setup the NavMeshAgent
29.  
30.         m_navMeshAgent = GetComponent<NavMeshAgent>();
31.  
32.         if (maxMoveSpeed > moveSpeed)
33.         {
34.             // If the Max Move Speed is great than Move Speed, then return a random Final Move Speed between the two
35.             // If the Chase Multiplier is greater than 1, multiply the Final Move Speed by the Chase Multiplier
36.  
37.             if (chaseMultiplier > 1f)
38.             {
39.                 finalMoveSpeed = Random.Range(moveSpeed, maxMoveSpeed) * chaseMultiplier;
40.             }
41.             else
42.             {
43.                 finalMoveSpeed = Random.Range(moveSpeed, maxMoveSpeed);
44.             }
45.         }
46.         else
47.         {
48.             // If there is no Max Move Speed, then code uses the Move Speed, and again checks if there is a Chase Multiplier
49.  
50.             if (chaseMultiplier > 1f)
51.             {
52.                 finalMoveSpeed = moveSpeed * chaseMultiplier;
53.             }
54.             else
55.             {
56.                 finalMoveSpeed = moveSpeed;
57.             }
58.         }
59.  
60.         if (m_navMeshAgent != null)
61.         {
62.             playerTarget = GameObject.FindWithTag("Player").transform;
63.             m_navMeshAgent.updateRotation = false;
64.             m_navMeshAgent.updateUpAxis = false;
65.             m_navMeshAgent.speed = finalMoveSpeed;
66.         }
67.     }
68.  
69.     void Update()
70.     {
71.         // Distance to player calculations
72.  
73.         playerPos = playerTarget.position;
74.         relativePos = playerPos - (Vector2)transform.position;
75.         distance = relativePos.magnitude;
76.         transform.position = new Vector3(transform.position.x, transform.position.y, 0f);
77.  
78.         if (distance > attackDistance)
79.         {
80.             if (m_navMeshAgent != null)
81.             {
82.                 m_navMeshAgent.destination = playerTarget.position;
83.             }
84.         }
85.         else
86.         {
87.             // Attack when player is within Attack Range
88.             // Attack code here
89.  
90.             Debug.Log("Attack");
91.         }
92.  
93.         // Rotate the enemy to face the target
94.  
95.         float angle = Mathf.Atan2(relativePos.y, relativePos.x) * Mathf.Rad2Deg - 90f;
96.         transform.rotation = Quaternion.Euler(0f, 0f, angle);
97.     }
98. }

 

A bit more info on the issue - I run away from the AI down screen, it follows fine, until occasionally the Agent just stops, or perhaps just moves very slow.

If the player then changes direction and moves left or right, the AI wakes up and resumes chasing as it should.

 

Hi,

First thanks for this great package!

It seems I have a similar problem than @supericon .

In my little game, the agent (the zombie) regularly recalculates a new path towards the target (the player). But whenever the agent is chasing the target vertically, at some point, the agent seems to be stucked and only moves super slowly. This issue only seems to appear when the agent moves vertically. If the target moves a little bit on the left or right, the chasing resumes correcly.

FYI, I am using the setCalculatePath and SetPath functions and I'm using NavMeshPlus 0.1.0.

I made a video to illustrate the problem:

Any idea?
Thanks,
Regards,
Sam

 

Hi Sam - yep, sounds like the same thing - vertical player movement, AI agent chasing, often the AI just stops after a while and then moves super slow, but if you move left or right, the AI agent wakes up and resumes the chase.

 

Hello, @supericon and @sammarin

NevMesh Plus only bakes a navmesh, afterward it's all Unity components. I'm aware of this issue with WASD movement, but it's unexpected for SetDestination().

Here is similar issues:
https://github.com/h8man/NavMeshPlus/issues/21
https://github.com/h8man/NavMeshPlus/issues/20

I cannot find original post, but Agent.destination = player.position+new Vector(0,0.0001) had fixed the issue to prevent straight vertical movement.

 

On the x? Like this:

m_navMeshAgent.destination = playerTarget.position + new Vector3(0.0001f, 0f, 0f);

Although, I tried it on all axis just to be sure, and it doesn't fix it

 

@supericon ,

Send my a test project, as you mentioned earlier, I would take a look.
But, that 100% not NavMeshPlus issue, so while I'm trying to find what's happening, keep looking inside https://forum.unity.com/forums/navigation.79/

Try to reach Unity staff if you are lucky)

 

Thanks That would be awesome - test project sent via DM.

 

Quick update.

I didn't find issue to be caused by direction of the agent to target, but the agent in 95% stuck on the same spot of the navmesh. I'm trying to output Agent path state to catch what is happening, but with no luck.

So, I found workaround that I was talking about, but its should not be a constant, rather function.
The simplest solution is to add drift to the target position

Code (CSharp):

1.    var agentDrift = 0.1f;    
2.    var driftPos = playerTarget.position + (Vector3)(agentDrift * Random.insideUnitCircle);
3.    var res = m_navMeshAgent.SetDestination(driftPos);

Also issue can be caused by re-path on every frame. I will test and reply shorty

 

Hi @vhman and @supericon,

I also implemented a workaround. I'll explain to you here:

• The problem seems to happen when velocity.x of the navmesh agent is equal to 0
• So in the update function, at each frame I test if the velocity.x of the navmesh agent is equal to 0
• If this is the case, I recalculate a new path for the agent (using CalculatePath and SetPath) but with a target position.x to which I add 0.2f
• That way, velocity.x of the agent ceased to be 0 so the agent can keep going walking on the newly defined path (which goes a little to the right)

Of course, that way, the agent will sometimes slightly moves a little on the right while chasing the target but since I recalculate regurlarly the path (for example every second), the global behaviour is still OK

 

Thanks @vhman & @sammarin - that is amazing. Must admit, I took a few days off over Christmas, so haven't had a chance to test, but I shall update the code and take a look. Thanks again guys

 

Does anyone know why having a rigidbody2d would cause my baked nav mesh to have an offset?

Sorry for the bad resolution:
https://imgur.com/a/HUezbUN

Thanks for the asset vhman, you rock.

 

Thanks for the quick fix ! And ofcourse thanks for your super asset, really great stuff, man!

Been trying to solve the same issue (mentioned by @supericon and @sammarin) by means of rigidbody, trying to put force.impulse to it at every start of the pathfinding, but this is certainly NOT the way to go

Also, your quick fix had some minor, solvable implication for my check of arrival at the targetpoint, solved it by minimalizing the drift (0.0001) and getting a minimal stopping distance (0.1). To whom it may concern, code below..

Happy New Year !

Code (CSharp):

1.  
2.     void StartMovement(GameObject target)
3.     {
4.         // Quick fix of vhman !
5.         var agentDrift = 0.0001f; // minimal
6.         var driftPos = target.transform.position + (Vector3)(agentDrift * Random.insideUnitCircle);
7.         agent.SetDestination(driftPos);
8.     }
9.  
10.     void CheckArrival()
11.     {
12.         // Check if we've reached the destination
13.         if (!agent.pathPending)
14.         {
15.             if (agent.remainingDistance <= agent.stoppingDistance) //  stoppingDistance minimally set in editor to 0.1f
16.             {
17.                 if (!agent.hasPath || agent.velocity.sqrMagnitude == 0f)
18.                 {
19.                     arrived = true;
20.                 }
21.             }
22.         }
23.     }
24.  

 

Hello,

It seems to be a bug in matrix calculation. I will take a look in a few days.

@Lowrc I will add it to wiki cause its trouble to search for the same topic every time, thx
@sammarin if you have snippet, please post it below, I will add it too

 

I haven't seen the fourth one, but a bug in the matrix is definitely something to worry about.

By the way, I'm on 2020.3.24f1, let me know if you need more information. Thanks!

 

Does anyone know what this piece of code does?

Code (CSharp):

1.  
2.             if (collider.attachedRigidbody)
3.             {
4.                 Vector3 scaled = Vector3.Scale(collider.transform.position, builder.overrideVector);
5.                 src.transform = Matrix4x4.TRS(scaled, collider.transform.rotation, Vector3.one);
6.             }
7.             else
8.             {
9.                 src.transform = Matrix4x4.identity;
10.             }

Why would my polygonCollider2d having a rigidbody affect it's location?

This is what is making my navmesh bake in the wrong location.

builder.overrideVector = "(1.0, 1.0, 1.0)"
collider.transform.position = "(-0.3, 0.6, -0.1)"

scaled does not change as result of scaling, it stays
scaled = "(-0.3, 0.6, -0.1)"

src.transform.toString() = "1.00000\t0.00000\t0.00000\t-0.27274\n0.00000\t1.00000\t0.00000\t0.59669\n0.00000\t0.00000\t1.00000\t-0.06651\n0.00000\t0.00000\t0.00000\t1.00000\n"

I don't quite understand what's the purpose of the TRS method.

Now that I inspect it's manual, the TRS specification is:

Code (CSharp):

1.  
2.         [FreeFunction("MatrixScripting::TRS", IsThreadSafe = true)]
3.         public static Matrix4x4 TRS(Vector3 pos, Quaternion q, Vector3 s);
4.  

While the NavMeshBuilder2d is the other way around, the scale is the first parameter and what I assume would be the translation in third param.

 

Hello @g3trans

I didn't have time to look at transform, holidays etc.

The code you mentioned is taken form https://github.com/Unity-Technologi...vMeshComponents/Scripts/NavMeshSourceTag2D.cs

The purpose of the method is to transform mesh to its world coordinates.
You can remove this code if it fixes your issue.

I have planned to check matrix transform on this weekend.

 

Hello @g3trans

I played for few hours in troubleshooting. I noticed that rigid body and collider are not the same objects so I was able to reproduce it quickly, but that I stuck.

collider.CreateMesh(true, true) didn't give me desired result, as 2 duplicated objects with different rigid-body had the same Hash. So it bakes wrong mesh. Maybe it's a fluke?

Than I read documentation!
useBodyPosition:
// Should the mesh be transformed by the position of the attached Rigidbody2D?
So of course you should not use collider for matrix transformation but rigid-body!

Issue fixed for now. Code should be available on GitHub page.

 

@MelvMay,

I have at least 4 "Stones" with box collider 1 by 1, two of which have rigid body. And Hash is unique for each of stones. But if I duplicate those stones (now its 8 objects), only stones with rigid body have the same Hash, while stones without rigid body are unique.

Case1: "Stones" without rigid body are unique - yes, as it has its own matrix, so we supply Matrix4x4.Identity (that's fine)
Case2: "Stones" with rigid body unique - why? it is the same box collider but with rotation and rotation is applied afterward in my own matrix.

Behavior of Hash is kind of tricky. I use it only for cache, so it dies not disrupt functionality.

 

Hi, I am using the following config:


If I paint the collider to the tilemap by hand and hit Bake, it will work:


But when I update the tilemap by code and call `BuildNavMeshAsync()` in runtime, it looks like the newly added tiles are not taken into account. Do you know what I did wrong?

 

Hello @EricChan13412

I believe you changed tilemap and bake immediate, while collider geometry update later on a frame (or even after few? not confirmed).
Consider to update navmesh after geometry had changed, as @MelvMay mentioned you can check it in coroutine or force change immediately.

Also there some notes form manual, if it makes sense:

Important note: Collider's bounds not getting updated to match the transform until 'LateUpdate()' is called. Force the update by calling Physics2D.SyncTransforms() before calling 'BuildNavMesh()' if you baking navmesh at runtime.

Important note: Physics updated only in fixed update, that is running in different time period than regular update. So its is not possible to generate physics in Awake/Start and call 'BuildNavMesh()' before 'LateUpdate()' to bake new geometry at runtime.

More samples can be found in "NavMeshComponents" repository on GitHub and NavMeshBuilder methods documentation at Unity site

 

Hi guys, despite reducing my agent radius to the minimum, I can't manage to reduce the gap between the graphics and the mesh (as shown in the figure).

Any idea?

 

@chunky_octopus Hello

Is it tilemap? Please refer to this closed issue https://github.com/h8man/NavMeshPlus/issues/67
If you didn't get results, please make another post with size of agent, tilemap cell and mesh voxel