Is it better to have more or less triangles in a cell in a mostly empty room were the ground can be covered in a few large triangles or is it better for the ai if i use many smaller triangles to fill the room. thanks in advance for all help given.

Use the biggest ones possible, and then use "Balance for Optimization" on the pop-up navmesh toolbar, and then make one final pass and correct what optimization messed up.

But, save the file a whole lot.

ok thanks so less equals better overall then

Yea, if you have a large square empty room, its better to fill it with 2 large triangles then like 10 smaller ones. The bigger the better for navmesh.

Thanks again fellas, much appreciated.

Let "Balance for Optimization" pick your triangle sizes, is what I'm saying. Sometimes it will divide up your huge triangles - when it does, let it.

yhea it did that not 10 minutes ago, two large isosceles to a hand full of equal laterals thanks

EDIT: just spoted the 101 tips has a good deal of nav mesh tips inside it