The FK/IK system in CAT lets you simply push your character into the pose you want without having to worry about the too much about IK and FK. Most of the control you'd normally associate with IK is also present in FK as well and vice-versa.
One of the features of the CATRig is that if you move a bone in the hierarchy (regardless of whether you are in IK or FK), the bones on either side rotate to accommodate the move. This is system allows you to just manipulate the rig quickly and intuitively. This system is called Effect Hierarchy. Following are three examples of this.
Arm position before edit
Arm position after moving forearm
Moving the middle digit bends up the finger.
CATRigs have two types of spines, procedural and FK, both of which you can work with in much the same way. The main difference is that FK spines have PRS controllers on every spine bone, which means you can transform them individually. Be aware that FK spines have limitations as well.
Original pose: Select the ribcage.
As you move the ribcage, the spine interpolates with it.
Sometimes you want to adjust the pelvis (parent hub) without affecting the ribcage (child hub). For this purpose CAT has a feature called Pin Bone, which lets you manipulate the pelvis without affecting the ribcage.
As the pelvis is transformed, the ribcage remains stationary.
While you can transform fingers (digits) directly, you might prefer to use the instead. Its controls give you the ability to edit selected fingers’ spread, bend, roll, and curl. Digit Manager also has a built-in digit-pose preset manager.
Select the palm.
In the Digit Modifiers list, highlight the digits to edit.
Drag the Curl spinner and the fingers curl in.
Select the Footplatform. When you select it you can already see the Foot Pivot.
Move the pivot to the front of the FootPlatform.
When you rotate the FootPlatform it now rotates from the toe.
When you right-click a selected hub in Animate mode, you’ll find the Pin Bone command on the Tools 2 quadrant. When this control is on, you can, for example, edit the base hub (such as the pelvis), without affecting the position and rotation of the tip hub (such as the ribcage). See .
Multiple tail links selected
When rotated up the tail curls smoothly
An easy way to edit the collarbone rotation is to select the upper arm or shoulder bone and move it. When you move the upper arm bone, the collarbone will be rotated according to your movements. Alternatively, select the collarbone directly and use the Move, Rotate, and Scale tools.