We have a problem where, after starting Unity, the editor is mostly unresponsive for about 10 minutes or so. The project has a very large terrain but did not behave this way prior to upgrading to Unity 5.5. The basic symptoms are that the project loads with relatively high CPU utilization and the editor is displayed. Then Unity appears to be reading and processing the project files in some way with low but steady CPU usage (~25%). During this time the editor is extremely unresponsive so whatever this task is it seems to be taking place on the UI thread. Once this process is finished everything works fine again.
I’m not sure what to do to diagnose this but it is getting pretty aggravating to have to wait several minutes just to get started. Does anyone have any suggestions on what this might be and how to fix it?
The time the editor requires to open a scene highly depends on the number of GameObjects in that scene, but it has been like this prior 5.5 as well. I’m thinking about trees and grass patches on the terrain, are these perhaps separate GameObjects and go into ten-thousands?
I did some experiments with bigger scenes lately and figured out a few things that might be of interest, see this post.
This. I pretty much delete the library folder every time I upgrade a project. Everything reimports, which can take a fair bit of time. But it only happens once.
I gave deleting the Library folder a shot but after a few hours for it to regenerate the symptoms remain the same. I don’t think the issue is the number of game objects as the terrain doesn’t include trees and so on, the terrain is just large in terms of area. The main terrain is around 380 square km, but again we’ve been using this terrain for a while and it didn’t cause this problem until the 5.5 upgrade.