"Navmesh needs to be rebuilt" after update to 4.8

anonymous_user_d1c0a6e61 · June 11, 2015, 2:37pm

Hey, I have problem with navmesh on my level after upgrate fro 4.7 to 4.8.

The level is the same, copy of the same project, navmesh exist on the map (green mesh) but in the game my pawns can’t move and there’s info “Navmesh needs to be rebuild”. I built path of course, but still there’s something wrong…

Is there something new i should know after move from old version?

anonymous_user_dc029b20 · June 12, 2015, 8:01am

My navmesh becomes broken if I change something in NamMeshRecast settings. I have same message “Navmesh needs to be rebuilt” and I think it’s a bug and it was in 4.8 Preview too.

MieszkoZ · June 12, 2015, 3:55pm

Have you tried resaving your maps?

Cheers,

–mieszko

muchitto · June 16, 2015, 9:42am

I tried this and it didn’t work. I have sub levels under my persistent level and if I load the persistent level, it keeps saying the same thing no matter how many times I rebuild my level. When I load the individual levels it doesn’t show the message.

anonymous_user_b9532c9a · June 16, 2015, 2:51pm

Hi everyone,

I attempted to reproduce this on my end, however I haven’t been able to do so. Can you provide me with detailed reproduction steps that I can follow? Currently my sublevel containing the navmesh comes in and, on PIE no errors occur and my AI as well as my player are freely able to move across the navmesh surface.

Hevedy · June 17, 2015, 9:02am

Same problem here with the SurvivalGame project C++ series example, after change some in the navmesh from default map now build the navmesh but at play say need to rebuild and the bot don’t work…

anonymous_user_68436a09 · June 17, 2015, 10:07am

Same problem here. After editing the settings of “RecastNavMesh-Default” (this is the navMesh that ist generated for the NavMeshBoundsVolume) noone moves anymore and unreal keeps asking me to rebuild navigation. Even if I tick checkbox “Force rebuild on load” noone moves and unreal asks me to rebuild navigation.

summary:
leave default navmesh settings → everything fine.
edit navmesh settings → “rebuild navigation” bug.

anonymous_user_b9532c9a · June 17, 2015, 5:37pm

Hi ,

What specific changes did you make to the RecastNavMesh-Default?

anonymous_user_68436a09 · June 18, 2015, 9:31am

Hi ,
so today morning the bug was gone. I managed to reproduce the problem though: if I changed the cell size or Agent Radius of the navigation mesh (in the project settings or the RecastNavMesh-Default, regardless) Unreal starts aksing to rebuild navigation even though I rebuild. A restart of the editor is enough and the problem ist gone. BUT: The agent radius keeps resetting to 35 (from my lower values 25 or 20). And this reset occurs even if I change it in the project settings and the RecastNavMeshDefault.

summary: restart editor-> bug gone. But: Agent Radius resets to 35.

Cheers,

MieszkoZ · June 18, 2015, 11:02am

This is a know UX issue. All you need to do is to add SupportedAgent to NavigationSystem. This is done via the project settings.

Hevedy · June 18, 2015, 11:25am

If download the survival seriesgithub.com/tomlooman/EpicSurvivalGameSeries and open in the 4.8, check the map default , you need to change the recastnavmesh cell size to something like 10, yes if you change from the project works but at rebuild without restart the engine etc don’t work and i don’t need the same size in all maps…

MieszkoZ · June 18, 2015, 11:32am

We currently don’t support per-level navmesh tweaking. We’re going to add that, but it requires a lot of decisions, like what happens if you stream one-param-set level into different-param-set? We won’t be able to merge the navmeshes. And stuff like that. It’s hard

Raed_Abbas · October 27, 2015, 12:30pm

Yes, I noticed same thing. I have same problem with 4.9.2. I ended up deleting the navmesh and create new using only default settings. The only parameter I could change without getting problems is the Cell Height. If I touch anything else I get the bug. I also noticed that UE crashes if you move the Navmesh in a folder in the World Outliner.

anonymous_user_b9532c9a · October 27, 2015, 2:54pm

Hi ,

The crash is concerning, however it would be best to address it in its own answerhub post. Can you make a new post and include the following information:

Crash logs (\Unreal Projects\PROJECTNAME\saved\logs)
Callstack
Dxdiag
Steps to reproduce error
Whether this occurs in a clean, blank project with no additional content or is limited to one project
C++ or blueprint based project?
Launcher or Github editor build?

For the parameter changes, what steps are you taking for me to reproduce this on my end? Does this occur in a clean, blank project as well? Which specific parameters are you trying to change and where are you trying to change them?

gaga071985 · November 9, 2015, 4:54pm

Hello,
I have same problem. I am 4.9v.
A solution does exist ?

Henrik · November 10, 2015, 2:30pm

Hi I just fixed this in 4.9.0 by doing what MieszkoZ mentioned above in this thread on Jun 18 '15 at 11:02 AM:

“This is a know UX issue. All you need to do is to add SupportedAgent to NavigationSystem. This is done via the project settings.”

Give it a go!

Henrik · November 10, 2015, 2:31pm

This worked for me. Thanks MieszkoZ!

gaga071985 · November 11, 2015, 8:07pm

Unfortunately, that don’t work. Would there be another solution?

anonymous_user_b9532c9a · November 16, 2015, 3:53pm

Hi gaga071985,

I looked a bit further into this and unfortunately at present the method suggested by Mieszko earlier is the only way to accomplish this.

gaga071985 · November 16, 2015, 4:39pm

Thank you for your reply. If I find the cause of my problem, I will share. Good evening .