Increasing Navmesh Cell Height Crashing Unreal When Opening that Level

Hello everyone! I’m new to Unreal and never had anything to do with game design, so I’m a true newbie here, but I’ve been watching tutorials, learning as I go and having a load of fun. I’ve encountered my first problem that I haven’t been able to figure out…

My game is VR. My level is an 8129 landscape that I created from a heightmap. It’s an outdoor map - no flat surfaces for our players but hills and winding ravines. After adding the Nav Mesh Bounds Volume, I increase the dimensions of the volume to encompass the map. The “green” Nav Mesh shows up in a couple isolated spots but it’s not covering hills. I figure it needs to be taller and learn a little more about how Nav Mesh works. I increase cell height and Wammo: the Nav Mesh totally covers everything perfectly. I save, grab my VR goggles, open the level and…crash. The level won’t open. The moment I hit the “open” button, it freezes up.

I’ve since tried rebuilding the level fifty times to test. Saving a level with flat, 10.0 cell height Nav Mesh will work and the level will load just fine. Increase the height even a few points and it won’t load anymore.

A few other tests I’ve done that might be helpful…

  1. I’ve loaded the Nav Mesh fine when I didn’t increase the height, but did increase Agent Max Slope for the hills. That loads fine, but the Nav Mesh isn’t covering the area.
  2. I’ve tried this at Cell Height levels ranging from 25 to 300. For me, 250 is perfect. No matter how much or how little the increase, the level will not load.
  3. I’ve tried increasing the Cell Height for Low, Default and High. I’ve also tried Default only. The level won’t load.
  4. I totally uninstalled Unreal 5 and reinstalled it again. Same problem.

But then again, I don’t know…

  1. Is there a maximum size to the volume? Is it just to dang big?
  2. Is there another way to go about covering my area in Nav Mesh? Every online tutorial I can find shows a dude on a flat floor.
  3. Do you guys do the Nav Mesh first, or do you completely design you game first and do Nav Mesh towards the end? If so, how do you test it in VR if you can’t teleport around?

Thank you all in advance for the help. I’m not letting this setback deter me as I was having way too much fun.