It is very unnatural to see a whole line of terrain bushes disappear in front of your eyes at a relative not too far distance and then appear again at a closer distance. I tried the main camera near and far clipping settings, but I was unable create a more realistic look. What do you suggest? Many Thanks.
One way would be to put environmental fog a certain distance from the camera so you don’t notice, but most games use what’s called Level of Detail (LOD). As the camera is further away, the objects gets replaced with lesser detail versions. More information about LOD can be found in the docs:
http://docs.unity3d.com/Documentation/Manual/LevelOfDetail.html
Unfortunately, it’s only available in the pro version. You might be able to script your own LOD system, but I’m not sure about that.
If you’re using the built-in terrain features for the trees, it kind of automatically does this by replacing the mesh trees with billboard trees at a certain distance. Descriptions of the settings can also be found in the docs:
http://docs.unity3d.com/Documentation/Components/terrain-OtherSettings.html