Naming Objects and Using Datablocks
Before proceeding, you need to learn how to rename objects. This skill will come in handy when you’re working in really complex scenes and want to recognize objects by their names. Otherwise, you’ll find yourself lost in a sea of objects called Plane.001, Sphere.028, and other generic names.
If a Blender scene were a wall made of bricks, each brick would be a datablock. Every object in Blender has a datablock inside that represents its contents. Datablocks can be named and used in different ways that I talk about in the following section.
You have several ways of renaming an object:
Locate the object in the Outliner. Right-click its name and choose the Rename option from the contextual menu. Alternatively, you can double click the name. Type in the new name and press Enter to confirm.
In the 3D View Properties Region, you can rename the object in the Item panel. Left-click the text field, type the name, and press Enter to confirm.
In the Properties Editor, go to the Object tab (the one with a yellow cube); type the new name in the text field in the top-left corner; and press Enter to confirm.
Datablocks are the most basic Blender components. All the elements you can build—such as objects, meshes, lamps, textures, materials, and armatures (skeletons)—are made of datablocks. Everything in the 3D scene is contained in an object.
Whether you’re creating a mesh, a lamp, or a curve, you’re creating an object. In Blender, any object has object data (ObData) inside it, so the object itself acts as a kind of container for the data and stores information about its location, rotation, scaling, modifiers, and so on. ObData defines what’s inside an object. If the ObData is a mesh, for example, you see a mesh with its vertices and faces inside the object. When you access the ObData, you can adjust its parameters. If you click the drop-down list of the ObData datablock, you can load a different ObData into the object. You could load a different mesh into the object’s position, for example. Several objects can use the same ObData. (These objects are called instances or linked duplicates.) This means that even if the objects are in different positions in the scene, all of them synchronize their contents, so if you adjust the mesh vertices in one of them, the others reflect those changes. In this section, you look at a mesh and see the difference between the object and the object data.
Figure 3.3 shows how to check for an object’s name inside the Properties Editor. The image to the right shows that the Mesh’s Name is inside the Object’s Name. In the image, the ObData is a mesh; if it were a lamp or a curve, the icon would change accordingly. The Properties Editor always shows information about the selected object, but if you click the Pin icon, the currently selected object’s information is pinned, and even if you select a different object, the Properties Editor keeps displaying the pinned object’s information.
Figure 3.3 Properties Editor Object and Object Data tabs
To the right of some datablock names, you find an F button as well as a number. The number indicates the number of users that the datablock has. In Figure 3.3, the mesh ObData has two users, which means that two different objects are using that mesh data. (The scene has an instance.) If you want to turn an instance into an independent, unique datablock, just click the number. Blender creates a duplicate and indicates a single user for the new one.
If at some point, a datablock (such as a mesh or a material) has 0 users, and you close the file, Blender cleans out the unused datablocks in the file, so you lose that great material you created but weren’t using. That’s why the F button exists; it creates a fake user of that datablock. Even if you’re not using the datablock in the scene, that datablock has one user, which prevents the datablock from being deleted when you quit Blender. Datablocks that have zero users are called orphan data.
Keep in mind that you usually work with the names of objects. Most of the time, you don’t need to access the names of ObData like meshes inside objects, so if you are running low on time, you can generally skip ObData naming.
Naming Your Scene’s Objects
After you understand what datablocks are and how to rename objects, you can name the objects in your scene accordingly. (You might name the plane Floor, for example.) Sometimes, you have to select a datablock’s name from a list, so naming datablocks intuitively will help you find the one you’re looking for.