Wiring a Custom Attributeparameter wiring:character rig wiring:character rig custom attributes:character rig rig:wiring rig:custom attributes

Introduction to Character Rigging

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Autodesk 3ds Max Tutorials > Character Animation Tutorials > Character Animation without Biped > Introduction to Character Rigging > 

Using List Controllers

When you create any object, including bones, default controllers are placed on the object to control its position, rotation, and scale.

For each transform, you can change the default controller to a list controller. This type of controller allows you to assign two or more controllers to the transform. The controllers are evaluated from first to last, and their values are added up to give the final transform value.

When you assign a list controller to a transform, the first controller on the list takes on the transform's current XYZ values, and the next controller starts off with a value of [0,0,0]. Then you can make the second controller active, so any animation will change the second controller's values only.

By assigning a list controller to the objects in your scene, you effectively set their animation transforms to [0,0,0] on the second controller regardless of how much you have moved, rotated or scaled the objects up to that point. If you wire parameters between two objects on the second controller, the transform values will match, and one object's parameters will predictably affect the other object's parameters.

In the case of a character rig, you have probably rotated the bones and controls to fit them to the character. Wiring the rotation of these objects to one another without using a list controller will cause one object to take on the posed rotation of another. For example, if you previously rotated a control shape by 90 degrees on the X axis to make it fit the rig, then you wire the control shape's X rotation to a bone's X rotation, the bone will suddenly rotate by 90 degrees to match the wired parameter. In such a case, you can use list controllers to cause both objects to start from a 0 rotation, and ensure that the control object will predictably affect the bone.

This lesson illustrates how you can use list controllers in a character rig.

Prepare the scene:

1. Continue from the previous lesson, or open the file tut_introrig_wired.max.

   

2. If you are continuing from the previous lesson, go to frame 0.

   Right now, the control object CtrlSpine at the bottom of the spine can be used to rotate the character's entire spine. But when you twist your spine, your upper body rotates more than the lower part. You will simulate this motion by causing the upper spine bone, BoneSpine02, to rotate 1.5 times as much as CtrlSpine and BoneSpine01.

   To achieve this, you will wire the rotation of BoneSpine02 directly to CtrlSpine. When you rotate CtrlSpine, BoneSpine02 will rotate by the same amount due to its linkage to BoneSpine01 and an additional half of the rotation due to the wiring.

Align the pivot points:

Before you can wire BoneSpine02 to CtrlSpine, you must make sure their pivot points are aligned. Later, when you wire each rotation axis of BoneSpine02 to CtrlSpine, you will know that the rotation axes match.

1. Select CtrlSpine.
2. On the Hierarchy panel > Pivot > Adjust Pivot > Move/Rotate/Scale group, turn on Affect Pivot Only.
3. Use Align to align the CtrlSpine pivot point with the pivot point of BoneSpine02. On the Align dialog, choose Pivot Point for both the Current Object and Target Object.
4. Turn off X Position, Y Position, and Z Position, then turn on X Axis, Y Axis, and Z Axis in the Align Orientation group. Click OK.
5. Turn off Affect Pivot Only.

Assign a rotation list controller:

Now you will assign a Rotation List controller to CtrlSpine's Rotation track.

1. With CtrlSpine selected, go to the Motion panel.
2. On the Assign Controller rollout, highlight the Rotation: Euler XYZ track.

   Currently, the rotation track holds the default rotation controller, Euler XYZ.

3. On the Assign Controller rollout, click the Assign Controller button. Choose Rotation List from the list of controllers, and click OK.
4. On the Assign Controller rollout, expand the Rotation branch.

   

   The Rotation controller branch now contains three items: Euler XYZ, Available, and Weights. The Euler XYZ controller is the controller that was previously on the Rotation track, and it holds any rotation applied to the object up to this point. The Available controller is a placeholder for any controllers you want to add to the list.

5. Highlight the Available item.
6. Click Assign Controller. Choose Euler XYZ from the list of controllers, and click OK.

   The Rotation List controller now shows two Euler XYZ controllers.

   

Name the controllers:

When you wire the second controller later on, your work will be much easier if you give each of the controllers a unique name now.

1. On the Rotation List rollout, highlight the first Euler XYZ listing under Layers.
2. In the entry area below the Layer listings, enter InitialPose.

   The name of the first Euler XYZ in the Layer listings changes to reflect this new name. This controller holds the initial rotation for the object.

3. Highlight the second controller in the Layer listing, and enter the name Wiring.

   This is the controller you will use for wiring.

   When a controller is active, a small arrow appears to its left in the Layer listing. You will need to have the Wiring controller active when you animate the scene.

4. On the Rotation List rollout, click Set Active to make the Wiring controller active.
   TipYou can also double-click the controller in the Layer list to make it active.

Assign a list controller to the spine bone:

1. Select BoneSpine02, the highest spine bone.
2. On the Motion panel, highlight the Rotation track, and click Assign Controller. Choose the Rotation List controller from the list.
3. On the Assign Controller rollout, expand the Rotation listing. Highlight the Available listing, and assign a Euler XYZ controller to it.
4. In the Rotation List rollout, name the two controllers InitialPose and Wiring.
5. Make the controller named Wiring the active controller.
6. Save the scene as my_introrig_controllers.max.

   You can find a version of this scene in the file tut_introrig_controllers.max.

Wire the controllers together:

Now you can wire together the rotation axes on each object's Wiring controller.

1. Select CtrlSpine.
2. Right-click CtrlSpine, and choose Wire Parameters. From the pop-up menu, choose Transform > Rotation > Wiring > X Rotation.
3. Click BoneSpine02, and choose Transform > Rotation > Wiring > X Rotation.
4. On the Parameter Wiring dialog, enter X_Rotation / 2 as the expression.

   This will add half of CtrlSpine's rotation to BoneSpine02 on the X axis.

5. Turn on the right arrow, and click Connect.
6. Highlight the Y Rotation listing on each side of the dialog. Turn on the right arrow, and click Connect.
7. Do the same for the Z Rotation listings.
8. Close the Parameter Wiring dialog.

Test the wiring:

1. Rotate CtrlSpine on any axis.

   The lowest spine bone rotates by the same amount, but BoneSpine02, the higher spine bone, rotates a little more.

2. Turn on Auto Key.
3. Go to frame 10.

   The animation on CtrlSpine was lost when you assigned the list controller. The character is out of balance on this frame.

4. In the Front viewport, rotate CtrlSpine so the character leans in the direction opposite its hips.

   

5. Turn off Auto Key.
6. Save the scene as my_introrig_spinebend.max.

   You can find a version of this scene in the file tut_introrig_spinebend.max.