Links to cameras and lights .. has anything "changed" recently?

Trivial case:

– Start with default scene and save it.

– Open new file, delete everything. Next, “Link to” the object (not meshes…), camera, and light from that (default-scene) file.

I’m not seeing everything that I linked-to, in the new blend-file.

Not sure why.

Works fine for me. I opened a new file, saved it without alteration as TestLibrary.blend. New file, deleted the cube, lamp and camera. Ctrl-Alt-O, selected TestLibrary.blend, Object, shift-selected Camera, Cube, Lamp, hit enter. Everything shows up as expected. Did you do something different than those steps? Can you supply us with your two test files? And are you using an official release of Blender? What version?

:ba: … nevermind-d-d-d-d ​…

MBF (acronym): Momentary Brain-Fart.

:yes:

… or, to put it another way, “why you should not attempt to use Blender at odd hours, even though you often do.”

---- Edit:

I suppose it’s worthwhile to “fess up” to the details of my momentary stupidity for the benefit of the next poor soul. (Yes, you! Hi, there! I’m talking to you!) It’s quite easy to do, and not quite intuitive.

When you open a library file (and of course, any blend-file can serve as a library …) you will see a breakdown of everything that’s in it … including “cameras,” “lamps,” “meshes,” and so on. But these, really, are consistuent parts of what you probably want to be linking to … objects.

It’s quite easy to see “how Blender sees this” once you’ve done the linking … to objects … as Horseman pointed out. Switch to Outliner view, and there are the three objects: Camera, Lamp, and Cube. Now, expand each of those three nodes. Beneath them are identically-named “constituent parts,” which are owned by the linked objects.

As the Blender docs say, you probably then want to “Make Proxy,” and when you do this you’ll see the “_proxy” objects at the top of the Outliner hierarchy, with two things underneath each one. (One of them being the linked object.)

While you can link to “anything,” AFAIK, such as a “Mesh,” only Objects have a physical presence in 3D space. (You’ll have to make the association with an Object yourself before you can see them.) “Groups” are especially handy to link to.

Sigh … but, 'tis better to fess-up to oopsies, just in case thereby you won’t follow suit.

This is an easy mistake to make, and one that I still occasionally make despite knowing better myself.

It’s easy to expect that if you link something by clicking on “Mesh” then that mesh will show up in the target scene. Perhaps one might imagine the mesh would show up excluding other object data such as materials or object-level rotations and scales. In fact, this is not the case, because what you just linked isn’t the mesh itself, but the mesh datablock. That datablock could then be used on some other mesh object, but with no target object at the outset, the mesh has nowhere to go but to float off into Abstract Dataland until you tell Blender to use it for something. This video should clear things up for you or anyone else who comes across this thread in the future.

And, actually, the user-interface design is more than a little-bit at fault here, IMHO, because the icon that appears under “Camera” looks pretty-much identical to the one that appears under “Objects” for the Camera “object.” It doesn’t, IIRC, look like the “camera object-data” icon that you see when you drill-down on the Camera “objct,” even though it is my understanding that “object-data” is what is here.

It doesn’t, IIRC, look like “a datablock.” It looks like an object … and, quite honestly, it would make intuitive sense for another reference to “the object” to be what’s there. (You’d expect that node in the Outliner … the one in the “Cameras” section … to refer to the “object” and to have a drill-down. Or, if this is not to be the case, it shouldn’t look like what it looks-like now.

Pursuing this thought a wee bit farther … “linking to a mesh” apart from an object ‘makes sense could be useful.’ But … linking to a camera’s object-data, or a lamp’s? “Not so much.”

I can definitely see some user-experience improvements here. “A little-tiny picture conveys a lot of expectations,” and it seems to me that “things could be made better.”