Animation Constraints
Animation constraints define how certain Shaper objects move in relation to others. This relationship is defined by the object to be constrained, its target, and the type of constraint. Constraints can affect the position of an object, the orientation of an object, or both at the same time.
Animation constraints are defined in the Kinematics tab of the Shaper sidebar:
Select the objects to be constrained.
Click on the button to add a constraint to the selected objects.
A context menu appears. Select the type of constraint that will be created.
An eyedropper appears. Use this tool to select the target in the viewport. For example, if the selected null should follow a Bézier path, use the eyedropper to select the Bézier path.
Managing the List of Constraints
The list of constraints in the Kinematics tab shows the constraints applied to the selected object or objects in the Shaper viewports. To view all of the constraints for a model, select all Shaper objects.
Constraints are taken into account in the order that they are listed. The position and the orientation of an object are evaluated separately and assigned to the first constraint in the list that applies to them. Constraints further down the list will have no effect on an object's orientation or an object's position if it has already been constrained.
Constraints cannot create circular reasoning. When a new constraint would create circular reasoning, an error will appear indicating the object of the constraint causing the conflict. If you really want to create the new constraint, you must first delete the conflicting constraint from the list.
To modify an existing constraint, select it in the list. Use the button to activate an eyedropper, then select a new target in the viewport. The new target will replace the old target in the selected constraint.
Use the button to delete the selected constraint from the list.
Position Constraints
Position constraints assign the target's position to the object. If the target is a moving part, the object will also be affected by the changes to the target's position.
To avoid having two objects that occupy the same position in the 3D world, assign an offset to the constrained object. An offset is defined below the list of constraints using the XYZ coordinates to express the difference between the target's position and the object's position. When the target is repositioned, the object will also be repositioned and the offset distance will be maintained.
Orientation Constraints
Orientation constraints assign the target's orientation to the object. If the target is a moving part, the object will also be affected by changes to the target's orientation.
The object's orientation and the target's orientation are defined by their pivots, which set their local coordinates. The rotational transformation that is applied to the target's pivot will be applied to the object’s pivot.
Two methods exist for setting different orientations for the object and the target with an orientation constraint:
Modify the orientation of the local pivot for either the object, the target, or both.
Set an orientation offset below the list of constraints. The offset should be provided in X, Y, and Z angles. It will be applied to the object's pivot.
Look At Constraints
Look At constraints use the position of the target to set the orientation of the object. If the target is a moving part, when the target is repositioned in the 3D world, the object will rotate in order to face it.
The object’s face is defined by its pivot and by the settings below the list of constraints:
Setting | Default | Description |
---|---|---|
Aim axis | local X axis | Defines the local axis of the object's pivot that is oriented towards the target. |
Up vector | local Y axis | Defines the local axis of the object's pivot that points upwards. |
To make fine adjustments the alignment of the object's face, adjust the object's pivot.
Follow Path Constraints
Follow Path constraints allow an object to use a target Bézier curve as a path. When the Bézier curve's path constraint is animated as a channel animation, this affects the object's position. If the option Align to path is checked, it also affects the object's orientation.
The object follows the Bézier path starting from the path's start point and progressing in the same sense as the path. You can change the start point by:
Right-clicking on the Bézier path where the start point should be placed and selecting Place start here.
Modifying the Position along path setting below the list of constraints. Provide location along the Bézier curve by entering a percentage of the curve.
If the option Align to path is checked, the object will rotate so that its face is always oriented in the direction of travel along the Bézier path. Below the list of constraints, you can define:
Setting | Default | Description |
---|---|---|
Aim axis | local X axis | Defines the local axis of the object's pivot that is oriented towards the direction of travel along the Bézier path. |
Up vector | local Y axis | Defines the local axis of the object's pivot that points upwards. |