NVidia GT 240
Official Blender 2.77a (abf6f08)
Short description of error
I prepared an example for this bug.
- Open the "blend.blend" file. It should have a group linked relatively to the "link.blend" file.
- Render and look at the result. The monkey gets excluded from freestyle lines when it shouldn't.
As you can see, there are three cubes on front, 2 of them in a group which I decided to exclude from freestyle calculation through RenderLayers > Freestyle Line Set > Selection By: Group > Group: Group > Exclusive
So, our linked library IS NOT within the excluded Group named "Group, and so, no linked object should be excluded.
Looking carefully in the Outliner, one can see why this is happening, just by the simple reason that one of the excluded cubes has the same name that the linked monkey head, so, for Blender is like if that object IS inside the excluded group, so he decides to exclude it from the result. You can prove that by changing the name of the cube named "monkey" to something else. Now the monkey head gets its freestyle lines as it should.
This is a very annoying bug when working on big projects, as it becomes really hard to "discover" between so many objects, the very reason why some of these aren't rendering properly in freestyle.
I think the solution is simple, it should involve some way of giving the linked objects a different ID or something internally, so that objects remain "different" for Blender.