I have made some trees to make a forest and each tree has its own file. Now I have appended them into one file and now I have like 40 unnecessary materials which are completely the same and each is assigned to a few objects, so that I would have to switch materials for about 200 objects to get rid of them. Is there some other way to merge the identical materials into a single material?
Select all the objects that share the same material. Using Select->Select Pattern may be a quick way to do that.
⎈ CtrlL -> Material will set the same material for each object.