Consider this scenario:
I have a scene with a mesh called “object-1”. This mesh belong to a group called “object-1”
I also have a scene called “RenderMe”
Inside RenderMe I have an empty which dupligroups object-1 into the scene. This empty animates along a path.
All fine and dandy save file to disk.
Ok , new scene.
I append “object-1” scene from that file and edit it so it is different from the original. But it still has the same name and belongs to the same group name.
So I want the animation from the original scene, but using my newly edited object.
I create a new “RenderMe” scene and File/Append the empty and the path.
Everything looks great, but for some reason it is not using my new object.
What seems to be happening is that Blender 2.5 is importing the empty, notices the dupligroup so it imports that mesh so it can display the mesh in the scene. But this mesh becomes a dangling mesh that is not accessible in any scene in the file but is still displayable because the empty has a reference to it.
If I switch to my “object-1” scene and add all those objects to a new group and use that new group name for the empty, I can fix the problem. I do a file save and the dangling mesh is gone on re-open.
But the problem here is more of a work flow issue. It does not make sense, to me, that Blender should operate this way, tricking you by showing you a mesh that you can not access. Also, using this workflow of appending new dupligroups I am plagued with mysterious crashes that I can not re-produce for developers. Undos, especially cause crashes to the point where I can no longer use that feature on my scene.
Ideally, if I import an empty, that is truly all I wanted Blender to import.If the group name is already in the file you are appending to, the empty should use the group in the file is is appending into, if not, just blank out the dupligroup field and leave it as an empty.
Maybe there are ways to tell Blender this is how I want it to operate, but I am new to 2.5 and it is full of bugs, I thought I’'d offer up my experience because other people may not be working with files in this fashion.