Unity has LODGroup’s, and there are several third party solutions with varying features that range from straight up replacements for LODGroups, to dynamic batching/LOD combinations. In all cases I have found, you can see a noticeable pop when switching from one LOD to another.
As of Unity 5, LODGroup’s now have a CrossFade Fade Mode option. However, it says you are required to write your own shader to handle it. I think that option simply reports the percent cross fade, then it’s up to you to handle it.
I read some info about SpeedTree, where they fade in one LOD, fade out another.
Is there a readily available solution to support CrossFade, or some other solution to prevent or reduce popping of mesh LODs?