For some reason, I am unable to get navmeshes to work when using Play In Editor, even in a default Third Person project. In the editor viewport, the navmesh is visible and editable, but when I hit Play, I am unable to see the full navmesh even after enabling visualization of it (using ’ key and numpad 0). The output log states “WARNING - PATHS MAY NOT BE VALID” (full section of log below).

The screenshots and log are from 4.9 preview 4, but the exact same tests were done with 4.8 as well, with the same results. In a separate project I was unable to get an AI character to move, which is what led to this discovery (see question for details: [previous noobish question][1])

And the Output Log: [link text][4]

Any help would be immensely appreciated, I’m sure there’s some simple fix but I’ve so far failed to find one!


Just as a quick update, I’ve downloaded 4.9 and switched to Windows 10 with no apparent changes to this issue. Another oddity has come up in a different level, wherein the Navmesh builds just a bit around the player during PIE, appearing to rebuild every few seconds. It is far from the full Navmesh though, and the same error appears in the output log upon starting PIE. I may write out a new question for that tomorrow.

I am happy to provide any other info too if someone can help, this problem is preventing just about any use/ testing of AI and that is just no fun!

And now I’ve loaded UE4 onto another computer, downloaded everything from scratch, started a new project, and the same problem is occurring. This suggests the problem is that I am forgetting some crucial step in navmesh creation, which is at least nice because there should be a solution! However, I can’t for the life of me figure out what it is.

I’ll keep commenting with updates in case it is useful to someone, but does anyone have a clue what is going on? Or has had this issue as well?

I am also running into this issue.

I had the NavMesh generating and working correctly and then all of a sudden after changing a few things it would not work and debugging the navmesh at runtime would result in the same sort of results as the OPs 2nd image.

The things i remember doing before this issue occurred are as follows.

I altered the dimensions of the Navmesh using the slider instead of inputting direct values.
I changed its Location.
I altered the Runtime Generation setting from Static to Dynamic.

That is all i can remember that might have some sort of relevance.

Im using 4.9 on Windows 10 64 bit.

The following is a video of what the NavMesh is doing. Im spawning in AI units during the course of the game and the NavMesh is doing some funny redraws.