3ds Max 2012 Bible - Kelly L. Murdock [421]
4. Open the Create panel and select the Sphere button. Enable the AutoGrid option at the top of the Object Type rollout and drag on the surface of the head to create two eyes and a nose.
5. Open the Modify panel again, select the head bone, and apply the Edit Poly modifier to the object. Then click the Attach button and pick the two eyes and nose objects to combine them to the head object.
6. Right-click in the Modifier Stack, select the Collapse All option from the pop-up menu, and click Yes in the warning dialog box that appears.
Figure 39.5 shows the custom alien head bone. You can switch back to the default box bone by disabling the Use Custom Mesh option.
FIGURE 39.5
Bones can be replaced with custom mesh objects.
Building a custom CAT rig
When building a custom CAT rig, start with the CAT Parent object, but make sure the None option is selected in the CAT Rig Load Save rollout. Then, right-click in the viewport to exit CAT Parent creation mode. This creates the parent without any rig. Position the CAT Parent object so both feet of the skin mesh are contained within the parent's outline.
Tip
If you make the skin mesh object frozen and enable the See-Through option in the Object Properties dialog box, you can easily place the rig bones where they need to be. •
The first step in creating a custom CAT rig is to create the pelvis using the Create Pelvis button beneath the list of presets. The pelvis object appears as a simple box object above the CAT Parent object. You can then use the Transform tools to move, scale, and rotate the pelvis into place to match the skin mesh.
With the pelvis object in place and selected, you then have options in the Hub Setup rollout, shown in Figure 39.6, to add legs, arms, and a spine or a tail if you want. The Add Leg button adds to the pelvis a leg with two bones that extends to the floor and an ankle. You can position the leg bones by dragging the foot into position. When one of the legs is in position, you can select the pelvis again and click the Add Leg button again to create the opposite leg. The opposite leg is created using the same settings and position as the first.
FIGURE 39.6
The Hub Setup rollout includes buttons for creating connected legs, arms, and spine.
With the pelvis selected again, click the Add Spine button. This adds a set of spine bones with another hub object on top. The top hub object is used to connect the arms and the neck. The neck is simply another set of spine bones with a hub object on top for the head.
Note
For creatures with multiple arms and legs, the difference between the limbs is that a leg extends from the hub to the ground, and the arm hangs loosely. •
You can then select the pelvis, shoulder, or head hub objects and use the Add Tail button to add a tail, wings, or ponytail as needed. Figure 39.7 shows a custom CAT rig created with only a few clicks. The rig includes IK chains on both legs and FK chains on the arms. Fingers and toes could be added easily by selecting the palm or ankle objects and specifying the number of digits.
Naming CAT bones
When bones are added to a CAT rig, they are automatically named using the text entered into the Name field. The default name of the entire rig is taken from the name entered into the Name field when the CAT Parent is selected, and names for each body part are associated with the various object parts such as RLeg and LArm. Each bone within a chain is given a default number, so the upper arm object is labeled as 1 and the lower arm is 2.
FIGURE 39.7
Custom CAT rigs are easily created using the CAT tools.
If you change the name field, all bone names that are affected by the name change are automatically updated, so changing the Name field in the CAT Parent to Reuben automatically changes all bones to start with this name. This makes keeping track of all the various bones much easier and intuitive. It also helps when you start to animate the rig.
Tutorial: Building a custom CAT rig to match a skin mesh
For this example,