[Figure 19] The scale manipulator in Maya allows for proportional scaling via the yellow box in the center of the object, and non-proportional scaling via the X, Y, Z manipulators.

Gimbal Lock
As we saw in the previous exercise, gimbal lock is the phenomenon of two rotational axes pointing in the same direction, making it impossible to rotate an object in a desired orientation. Gimbal lock is a major problem inherent in using Euler angles — it causes character TDs and animators a lot of grief and misery (and as you know, we’re often miserable enough as it is). Remember, gimbal lock is a by-product of using Euler angles, but Euler angles are the best way to represent your rotating objects graphically in a manner that you can understand and edit. Make sure that you take into account what axis you want to use as your twist, secondary, and primary, and change the rotation order of your object accordingly. Gimbal lock may be unavoidable, but it certainly can be contained.

Scaling
The last type of transformation we’ll discuss is scaling. You can use the Scale tool to change the size of objects by scaling proportionally in all three dimensions — X, Y and Z — or you can scale non-proportionally one axis at a time. Scaling has only one coordinate system, and is based solely on object space. (See Figure 19.)

[Figure 20] Cubes rotated 45 degrees, one about its center, one with the pivot moved to its edge.

[Figure 21] A sphere with its pivot point manipulator highlighted.

Pivots
The pivot of an object determines how it will transform within the 3D space. Specifically, pivots define an origin, or center, from which to rotate and scale. (See Figure 20.)

In most packages you have the ability to move the scale and rotate pivots to create the desired motion in an object. In Maya, a node’s pivots can be viewed and modified by pressing the Insert key when an object is selected. The following exercise will demonstrate how to select and relocate the two pivot points of an object together to alter how that objects transforms.

1. Choose Create > Sphere, and then select your newly created sphere (see Figure 21).
2. Press the W translate hotkey on your keyboard, or click the Move Tool icon.
3. Press the Insert key on your keyboard. The pivot of the sphere is located at 0, 0, 0 of the sphere’s local space.
4. Move the manipulator to adjust the position of the sphere’s pivot.
5. Press the Insert key on your keyboard to exit the Edit Pivot mode.
6. Press the E hotkey and rotate the sphere. Notice how the sphere now rotates around the newly placed pivot. Scale the sphere and watch as the sphere scales from its pivot’s location.