when i load my mod as the active file a warning pops up saying i have over 3000 vertices in level please optimize or finalize.
What should i do to correct this? should i use the auto vertice fill in tool or redo it not not cover some many nooks and crannys?
thanks for any advice as this error is not mentioned in the GECK Tutorial among many other things

Is that your navmesh kicking out that error? If you select your cell, it should say NavMesh (X Triangles) - X being the number of triangles. I think the limit is 2000. On the NavMesh toolbar (button to the right of the pencil), there's a button with a "B" on it (balance for optimization). That can help reduce the number of triangles, but can also do some really quirky stuff to the NavMesh.

Ya that's definitely a "too many navmesh triangles" error. Do what EzOn3 said and optimize, find cover edges and finalize. Then be prepared to fix what the optimization did to your navmesh.

I have the creeping feeling that you've sorta overworked your navmesh. You do not need to fill in nooks and crannies and in fact NPCs cannot walk in small spaces anyway and should not try, they just get stuck.

ok thanks a lot everybody i didn't know they couldn't get into narrow spaces.
i will def. use thebalance for optimization feature again, it is a pretty large level
so i may consider breaking into two parts thanks for the advice.