Offset constraints keep an offset between the driver and driven controls. In this example, we constrain a guitar (driven) to Electra’s cog (driver). We start with a scene that contains animation only on Electra:

1. In the animate state parameters, go to the Constraint tab.

2. In the Parameters section, set Constraint to Offset.

3. Select the guitar’s control.

   Note

   The two parameters below the Constraint parameter show the order to select the controls. For offset constraints, select the driven control, then the driver. If you select more than two controls before creating the constraint, the last selected control is the driver, and all the other controls are driven controls.

4. Hold ⇧ Shift and select Electra’s cog control.

5. Press H over the viewport or click on the top toolbar. A constraint is added and the driven control turns gray. A dotted line appears with an arrow pointing from the driver to the driven control, and you will not be able to move the guitar control because it is now constrained to Electra’s cog.

   

6. We want to constrain Electra’s left hand to the neck of the guitar. To do this, first create a locator on the neck of the guitar:

   • Enter the locator tool.

   • To create a locator, press H over the viewport or click on the top toolbar.

   • Position the locator at the neck of the guitar.

     Note

     If you are working with animation layers, the locator needs to be added to the current layer before you can move it. Select the locator, go to the animation layers pane, click the layer, and select Add Selected Controls to Layer.

   • Exit the locator tool.

   

7. Constrain the locator to the guitar so that as the guitar moves, the locator stays at the neck of the guitar. Select the locator, hold ⇧ Shift, select the guitar control, and press H over the viewport.

   

8. Constrain Electra’s hand to the locator - select Electra’s hand, hold ⇧ Shift, select the locator, and press H over the viewport.

9. Rotate Electra by setting keys on her cog control.

   Note

   If you are working with animation layers, the cog control needs to be added to the current layer before you can set keys on it.

10. The strumming hand doesn’t follow the guitar after rotating Electra, so create a parent constraint between the guitar control and Electra’s hand. This way, as the guitar (driver parent) moves, Electra’s strumming hand (driven child) moves along with it:

    • Select Electra’s right hand control.

    • Hold ⇧ Shift and select the guitar control.

    • In the animate state parameters, Constraint tab, Parameters section, set Offset to Parent.

    • Press H over the viewport.

We now have the following constraints added to the scene:

• The guitar is constrained to Electra’s cog.

• The locator on the neck of the guitar is constrained to the guitar.

• Electra’s left hand is constrained to the locator.

• Electra’s strumming hand is constrained to the guitar.

  

A lookat constraint allows an object to follow the path of another object. In this example, we add a lookat constraint to keep Electra looking at Flip.

1. Aim Electra’s head toward Flip.

2. In the animate state parameters, Constraint tab, Parameters section, set Constraint to LookAt.

3. Select Electra’s head control.

   Note

   The two parameters below the Constraint parameter show the order to select the controls. For lookat constraints, select the driven control (Electra’s head), then the target (Flip).

4. Hold ⇧ Shift and select Flip’s control.

5. Hover over the viewport and press H. A constraint is added and the driven control turns gray. A dotted line appears with an arrow pointing from the target to the driven control.

6. A control named <driven_control>__Target is created and this is the control that the driven object looks at. You can move the control away from the target object, which provides more flexibility on where Electra can look:

   The <driven_control>__Target control appears in the selection sets under All Controls ▸ constraints. The control is parented to the target object and can be animated.

A pin constraint allows you to keep a control at a certain position. A pinned control will not move, even if you move its parent control.

1. In the animate state parameters, Constraint tab, Parameters section, set Constraint to Pin.

2. Select the control(s) to pin.

3. Hover over the viewport and press H.

You can add multiple constraints to drive a single control. In this example, we add the following two constraints that drive Flip:

• An offset constraint that constrains Flip to Electra’s hand.

• A lookat constraint where Flip looks at a ball.

Constrain Flip to Electra’s hand:

1. In the animate state parameters, Constraint tab, Parameters section, set Constraint to Offset.

2. Select Flip’s control, hold ⇧ Shift, and select Electra’s hand control.

3. Hover over the viewport and press H.

Add a lookat constraint so that Flip follows the ball:

1. In the animate state parameters, Constraint tab, Parameters section, set Constraint to LookAt.

2. Select Flip’s control, hold ⇧ Shift, and select the ball control.

3. Hover over the viewport and press H.

You can set a constraint to be active within a frame range:

1. Select the driven control, hold ⇧ Shift, and select the driver.

2. Select the range of frames you want the constraint to be active for - hold ⇧ Shift and drag along the timeline.

3. Press H over the viewport. Keyframes and a bookmark are created for the frame range.

4. You can use the bookmark to adjust the frame range over which the constraint is active:

   • To move a bookmark, ⌃ Ctrl + or ⌃ Ctrl + drag the bookmark.

   • To resize a bookmark, ⌃ Ctrl + or ⌃ Ctrl + drag the ends of the bookmark.

5. Select the driven control and go to the constraint parameters, Blend section:

   • The blend value for the constraint is 1 within the frame range, and 0 outside the frame range.

   • You can adjust the effect of the constraint by changing the blend value.

   • Click to toggle display of the constraint bookmarks.

A transient constraint is a type of constraint that is only active within a frame range. Transient constraints differ from regular constraints in the following ways:

• When a transient constraint is created, keyframes are added for the driven control on every frame within the constraint frame range. A bookmark is also created on the playbar timeline to identify the frame range during which the constraint is active.

• The driven control can be moved around freely.

• Transient constraints only apply in the animation layer in which they are created. Regular constraints apply regardless of the layer you're on.

In this example, we transfer the ball from one hand to another. The original animation is shown below:

1. Constrain the ball to the hand:

   • Select the driven control (ball), hold SHIFT, and select the driver (hand).

   • On the timeline, select the range of frames to make the constraint active (hold SHIFT and drag along the timeline).

   • Hover over the viewport and press ⇧ Shift + H.

   A constraint is created between the ball and the hand, and keyframes for the ball are added on every frame in the selected frame range.

   Note

   The constraint behavior is only active within the transient constraint frame range.

   In the animate state settings, Constraint tab, turn on Show Preview Visualizer. This displays an arrow visualizer that shows the constraint relationship between the hand and ball:

   

2. Fix the position of the ball.

   Once the transient constraint is created, the driven object (ball) can be moved around, and the changes are automatically applied to the entire frame range the transient constraint is active. Make sure you are currently within the frame range where the transient constraint is active or the changes will not be applied to the entire frame range.

   Note

   If the changes are not applied to the entire transient constraint frame range, make sure that Auto Update Follow Ranges is turned on in the animate state settings, Constraint tab, Transient Constraints section.

3. Constrain the ball to the other hand:

4. Fix the ball on the second hand:

5. Fix the pop on the animation as the ball transitions from one hand to the other:

   • Select the ball (driven object).

   • Click in the timeline so that the current frame is within the frame range of the first transient constraint.

   • In the animate state settings, Constraint tab, Transient Constraints section, click the button. This updates the offset on the ball to match the frame after the current constraint range so that there is a smooth transition between the current range and next range.