Hello! I have a 2017x2017 landscape, and just added a navigation mesh volume. It took forever to build, and I will be adding trees and more props soon which will require a rebuild I believe. Is there a more efficient way to do this and improve build times? Or am I just going to have to deal with it? Thanks! 
Hi ,
This is to be expected. The single volume is having to calculate a large area when you use it in this way. This can be a very intensive process! It would be better to use smaller volumes that overlap slightly to get the job done. These overlapping navmeshes will all work together. You will not need it one single one to get the same effect.