I have so many books models to texture. Texturing them one by one will be a pain. Can Blender unwrap two (or more) separate meshes and make them share the same UV grid?
As long as all the vertices in your objects are completely connected to each other (no loose parts) the following technique will work:
Select all your objects, and press CtrlJ. This will join them into one mesh.
Press U > Unwrap (or whatever unwrapping method you want use).
- Press P > Separate by Loose Parts.
This works great for quick 'n' dirty unwrapping onto a tileable image, but it may make more sense to link them all (like Matt said). The simplest way to link them early in a project is to duplicate them with AltD instead of ShiftD. It will link the mesh and the UV map which will make things easier later on.
(Warning, this method might undo some work, so save before you try it)
Not precisely, no. But you can make all the models use the same mesh, IWC they would also use the same UV maps, and you'd only have to unwrap one of them. If they are all sufficiently similar, you can select all of the books and press ctrlL, then select "Object data." This will make all of the objects use a copy of exactly the same mesh (in fact, if you tab into edit mode for one of them, all the other linked meshes will also be highlighted as if they are also in edit mode). This way, you can edit the mesh (or UV map) for one, and the others will all use a copy of that.
Incidentally, if you want variation in the books, you can still move, rotate, and scale the OBJECTS independently. I.e. you can make one book fatter than the others by scaling the object on one axis, without changing the mesh.
Furthermore, you can make any or all of them unique individuals (no longer using copies of the same mesh, but rather each using their own mesh) without losing the UV map. Click the number next to the name of the mesh to "Make single-user copy." Then that one will be identical, but independent. You'd have to do this for each one, which might be tedious, but that only matters if you want them to be independent, like that.