there seems to be some inconsistency when loading obj. objects. sometimes it automatically applies the items materials other times not. specifically if i create a tree in another 3d program, with materials, then export in obj. format. sometimes the items parts (trunk, branch, leaves etc,) come up on the list for the multi shader under the surface shaders tab and sometimes they don't. how can i apply materials or textures if nothing comes up on the multi shader option? there is always the obj. file along with a mtl file also when i export my items. doesn't terragen automatically load the items materials when i load the object? i hope i explained my problem properly.
TG2 does automatically load materials if they are A: properly listed in the .mtl file and B: referencing image maps that are available to TG2 (i.e. not procedurals and not proprietary material properties such as reflection). Often other modeling apps will export incorrect .mtl definitions or are using procedural textures that are not properly rasterized for export.
To address specific problems I'd need to know more about the application(s) you are exporting from and what specific circumstances these problems occur under. What objects do work? What, if anything, are you doing differently in the cases where objects don't work?