Numerical input
Not only can you use hotkeys to activate the various transform modes, but you can also use the keyboard to explicitly input exactly how much you would like your object to be transformed. Simply type the number of units you want to change after you activate the transform mode.
As an example, suppose that you want to rotate your object 32 degrees around the global X-axis. To do so, press R ⇒ X ⇒ 32 and confirm by pressing Enter. Translate your object -26.4 units along its local Y-axis by pressing G ⇒ Y ⇒ Y ⇒ -26.4 ⇒ Enter. These steps can be a very quick and effective means of flipping or mirroring an object because mirroring is just scaling by -1 along a particular axis. For example, to flip an object along the global Z-axis, press S ⇒ Z ⇒ -1 ⇒ Enter. For consistency, these numerical input operations are also available when using the 3D manipulator.
As mentioned briefly in Chapter 2 when covering the Preferences editor, Blender has the ability to use mathematical equations as part of the numerical input system. This system is called the Blender’s advanced numerical input system. To take advantage of this feature, press the Equal (=) key before entering your numerical input. As an example, say you have a model of a car that’s 4.6 meters long; you want to move it along the Y-axis by 6 car lengths. Sure, you could do the math in your head (or with a calculator, if necessary), but it’s even easier to let Blender handle the math for you by pressing G ⇒ Y ⇒ =4.6*6 ⇒ Enter. This advanced numerical input system even allows for simple math functions and constants, such as sine, cosine, and pi (π). So, if you find that you need to rotate an object about its X-axis by the cosine of 2π (that’s 1°, by the way), you could use the following key sequence: R ⇒ X ⇒ =cos(2*pi) ⇒ Enter. If you’re coming from an industrial design or architecture background, this is an immensely useful feature.
The Sidebar
One other way to explicitly translate, scale, and rotate your object is through the Sidebar region (see Chapter 2) of the 3D Viewport. To reveal the Sidebar, go to View ⇒ Sidebar in the 3D Viewport’s header, or press N while your mouse cursor is in the 3D Viewport. The Sidebar sits along the right side of the 3D Viewport, and the Item tab of the Sidebar includes a Transform panel that allows you to explicitly enter numerical values (and simple math expressions) for Location, Rotation, Scale, as well as general Dimensions for your selection.
Chapter 4
Working in Edit Mode and Object Mode
IN THIS CHAPTER
When working on a scene in Blender, your life revolves around repeatedly selecting objects, transforming them, editing them, and relating them to one another. You regularly shift from dealing with your model in Object mode to doing refinements in Edit mode.
And this process isn’t only for modeling, but also for most of the other heavy tasks performed in Blender. Therefore, you can reuse the skills you pick up in this chapter in parts of Blender that have nothing to do with 3D modeling, such as animating, rigging, compositing, and motion tracking. Even if you don’t know how to do something, chances are good that if you think like Blender thinks, you’ll be able to make a successful guess.
Making Changes by Using Edit Mode
Moving primitive objects around is fun and all, but you’re interested in getting in there and completely changing the primitive objects that ship with Blender (described in detail in this chapter) to match your vision. You want to do 3D modeling. Well, you’re in the right place. This section introduces you to Edit mode, a concept that’s deeply embedded throughout Blender for editing objects. Even though this section is focused mostly on polygon modeling, also called mesh editing, most of the same principles apply for editing curves, surfaces, armatures, and even text.
Switching between Object mode and Edit mode
In Chapter 3, you do just about everything in Object mode. As its name indicates, Object mode is where you work with whole objects. However, Object mode isn’t very useful for actually changing the internal structure of your object. For example, select the cube in the default scene. You know that you can turn it into a more rectangular shape by scaling it along one of the axes. But what if you want to turn the cube into a pyramid? You need to modify the actual components that make up the cube. These changes are made by entering Edit mode.
There are a handful of different ways you can get to Edit mode. To get there by menu, left-click the Interaction Mode button in the 3D Viewport’s header. It should say Object Mode right now, because that’s the mode you’re currently in. From the drop-down menu that appears, select Edit Mode (see Figure 4-1). Be aware that if you’re working with an object other than a mesh, such as an armature, the contents of this menu may vary slightly to relate more to that object. However, with the exception of Empties (see Chapter 11), Lights, Cameras, and Speakers, all objects have an Edit mode.
FIGURE 4-1: On the left, the Mode button allows you to switch between Object mode and Edit mode for a selected object. On the right, the mode selection pie menu.