Patchy navigation mesh issue (spaces without navmesh + cluttered mesh generation )

[Deliriumz]

I tried finding a solution in the forum here, but no luck , so here goes :

We are using the navigation meshes for our pathfinding, and the generation of the navmesh works fine on flat BSP brushes, with a reasonably clean result. However, now that the actual terrain has been created by one of our artists, we've got an incredibly cluttered navigation mesh which has holes in them where just no navigation mesh is present whatsoever. Image below shows the problem :

http://imageshack.us/photo/my-images...onmeshpatc.png

The grey areas ( quite a big patch to the right ) are areas which just have no navigation mesh whatsoever, and the rest looks like my little pony threw up over the terrain. Is there any way of cleaning up the generation of the nav mesh ( apoligies if this is something really obvious, I've been doing other things than the navigation, and trying to get up to speed ), and to fill the gaps of the navigation mesh as well? I've tried adding own navigation boxes and linking them to the pylon but that was pretty much the same or worse result.

[brad4ever]

i have the same problem on terrain much much larger ... my only solution is decrease the size of pilon and place many more .

navmesh not seem to get along with landscape or there are property , poorly documented , that fixes the problems (although in the past i have done many test with poor results)

[Deliriumz]

Placing multiples doesn't really work too well for me . there are a few quite large outdoor maps in UT for example which seem to work fine. Wonder if theres anything we're doing wrong .

[Jetfire]

Im not actually seeing any holes in that pic, looks more like the navmesh is dipping a bit below the surface. You should see it if you hide stuff. This is only a problem if the height difference is so big that the ai can't hit it's movetargets.
Deleriums, UT3 used pathnodes, not navmesh, and those are still there to be used (with complete ut ai support)