Search in
Sort by:

Question Status:

Search help

  • Simple searches use one or more words. Separate the words with spaces (cat dog) to search cat,dog or both. Separate the words with plus signs (cat +dog) to search for items that may contain cat but must contain dog.
  • You can further refine your search on the search results page, where you can search by keywords, author, topic. These can be combined with each other. Examples
    • cat dog --matches anything with cat,dog or both
    • cat +dog --searches for cat +dog where dog is a mandatory term
    • cat -dog -- searches for cat excluding any result containing dog
    • [cats] —will restrict your search to results with topic named "cats"
    • [cats] [dogs] —will restrict your search to results with both topics, "cats", and "dogs"

[4.13] Navmesh Fail if Agent Radius > 39

Kind of a weird bug, we just migrated from 4.11 to 4.13 and noticed problems with the navmesh not respecting the defaults set inside of the project settings, when attempting to set the agent radius manually in the recast navmesh, the navmesh "looks updated" but disappears when attempting to play.

I was easily able to reproduce this in a blank project which I am providing here.

Here's the step by step instructions on how to reproduce it:

1 Create blank blueprint project, no starter content

2 On the template map you see after opening the project, add a NavMeshBoundsVolume and make sure you're covering a decent portion of the ground (can cover it all, not really important)

3 Build Paths

4 Play in editor

5 Move camera up to look at the terrain

6 Open console with ~ and type show Navigation (at this point you will see the ground navigation area just fine)

7 Exit play in editor

8 Open up the RecastNavMesh-Default

9 Increase Agent Radius to 40

10 Build Paths (should have been automatically re-done, but doesn't hurt to manually do it again)

11 Repeat steps 4 - 6 (you will notice navmesh no longer there when you play, but if you show navigation in the editor window it will still be there just fine)

12 You can try modifying Agent Radius below 40 and it will work just fine

Product Version: UE 4.13
navigation.zip (2.6 MB)
more ▼

asked Oct 06 '16 at 10:36 PM in Bug Reports

avatar image

1.2k 31 9 33

(comments are locked)
10|2000 characters needed characters left
Viewable by all users

1 answer: sort voted first

Hello MajinSephiroth,

I was able to reproduce this issue on our end. I have written up a report and I have submitted it to the developers for further consideration. I have also provided a link to the public tracker. Please feel free to use the link provided for future updates. Thank you for your time and information.

Link: https://issues.unrealengine.com/issue/UE-37017

Make it a great day

more ▼

answered Oct 07 '16 at 02:16 PM

avatar image

Rudy Q ♦♦ STAFF
47.2k 545 132 525

avatar image MajinSephiroth Oct 07 '16 at 03:06 PM

Update: NavMesh will also fail if Agent Radius < 30.01

avatar image MajinSephiroth Oct 12 '16 at 10:22 PM

Hey Rudy,

I saw that the bug tracker lists a date for "resolved". When will the fix be rolling out?

avatar image Rudy Q ♦♦ STAFF Oct 13 '16 at 01:47 PM

The issue was closed as by design. We currently don't support per-level navigation agent radius tweaking. It's done via project setting's Navigation System -> Supported Agents. I hope that this information helps.

Make it a great day

avatar image MajinSephiroth Oct 13 '16 at 02:55 PM

Alright, tested and works, thanks Rudy for making it a great day :)

avatar image MajinSephiroth Oct 28 '16 at 10:19 PM


I have bad news buddy.

4.13.2 kind of broke Navigation Mesh rebuilding if you modify the NavMesh Agent Radius to be anything.

You will be able to build navigation, and it will show, but the moment you leave the level, the navigation is gone.

I created a blank project to demonstrate this happening. If you open this up, you will notice the NavigationMap level has a navmesh volume, but no navmesh. Build paths, you will see the navmesh. Now open Empty map. Then open NavigationMap again, the navmesh is now gone.

Repo steps

  1. Create blank blueprint project

  2. Save default map as NavigationMap

  3. Add a NavMesh bounds volume

  4. Build navigation

  5. Open Project Settings > Navigation System

  6. Add a new Agent group, call it Test

  7. Change the Agent Radius to 90 (I also tested with 50, nothing else though)

  8. Delete the RecastNavMesh from the level and build Navigation again

  9. Open a new level

  10. Travel back to NavigationMap, navmesh gone

brokennav.rar (1.9 MB)
avatar image Rudy Q ♦♦ STAFF Oct 31 '16 at 06:17 PM

Hello MajinSephiroth,

I tested the project provided, however I did not see the issue that you are describing. I followed the instructions above for the example project. Are there any additional steps to reproduce this issue in the project provided? After clicking build the navmesh shows up and stays.

avatar image MajinSephiroth Nov 01 '16 at 06:09 PM

Did you try opening another map and then going back to the map with the navmesh?

avatar image Rudy Q ♦♦ STAFF Nov 01 '16 at 06:49 PM

That is correct. That was the last step that I took when testing the issue and it appears to working as expected. Could you try downloading the zip file that was provided and see if your results are different in the project provided?

avatar image MajinSephiroth Nov 01 '16 at 07:06 PM

Interesting, I was partially wrong in my bug report.

After step 7, perform the following step 7 a) Open Project Settings > Navigation Mesh, set the Agent Radius to the same value as the one used in step 7

Now it will do the un-expected behavior.

The navmesh will be completely fine the moment you re-launch the editor. However, if you perform a build of your game PRIOR to re-launching the editor after those settings, the navmesh will be gone.

Now, I'm not sure if this is intended engine behavior, but it raised great panic when it happened for me :p

avatar image Rudy Q ♦♦ STAFF Nov 02 '16 at 02:42 PM

After further testing I found that the switching between levels causes the show navigation check box to become unchecked. I believe this is the reason you are having this issue. If you check show navigation when returning to the level with navigation, this should resolve your issue. I hope that this information helps.

avatar image MajinSephiroth Nov 02 '16 at 03:40 PM

It's not the case for me, as long as I don't close down the project, the navigation mesh will never go back on after a level change.

Here's an example using the project I linked above: Video

avatar image Rudy Q ♦♦ STAFF Nov 02 '16 at 05:03 PM

I was able to reproduce the issue in the video provided and I have written up a report. However, the navigation comes back after building again. The report is for the issue of having to rebuild every time the level is opened. I have provided a link to the public tracker. Please feel free to use the link provided for future updates.

Link: https://issues.unrealengine.com/issue/UE-38129

Make it a great day

(comments are locked)
10|2000 characters needed characters left
Viewable by all users
Your answer
toggle preview:

Up to 5 attachments (including images) can be used with a maximum of 5.2 MB each and 5.2 MB total.

Follow this question

Once you sign in you will be able to subscribe for any updates here

Answers to this question