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Relations > Using constraints > Unlocking constraints

Unlocking constraints


By unlocking constraints, you can manipulate objects that are constrained to other objects. In other words, you can temporarily disable the constraints to modify their offsets.

In most cases you should unlock constraints before adding a new constraint to objects. Constraint parameters have default values that determine the offsets between the objects. If the Lock button is on, the default offsets are applied to the objects as soon as you add the constraints. For example, a spring constraint has a default rest length of 1 unit. When you add a spring constraint between a box and a Jack-in-a-Box, the Jack-in-a-Box will bounce around and stop at 1 unit from the box. If you want the Jack in a Box to end up in its original position, unlock constraints before adding the spring. This allows you to adjust the constraint offsets before they affect the objects.

To unlock constraints:

Click the Lock button so that it is in the unlocked position. You can also hold the U key while manipulating the constrained object.

Example: Unlocking a direction constraint
  1. Create a cone and a cylinder and move them apart.
  2. Multi-select the cone and the cylinder, in that order, then choose Relations > Direction Constraint.
  3. A constraint is added to the cone. When you move either object, the cone rotates to stay aligned with the cylinder.

  4. To display the constraint icon, choose View > Display > Constraints.
  5. You want the cone's tip to point at the cylinder. Turn on Rotate or press R and drag the cone. It does not move because its orientation is locked by the direction constraint.
  6. To unlock the constraint, click the Lock button so that it is in the unlocked position, or hold the U key , then drag the cone.
  7. The cone rotates.With constraints unlocked, you can adjust the offset.

    When you release the U key, or lock the Lock button, the constraints are active again. Now when you translate either object, the cone rotates so that its tip is always pointing at the cylinder.


See also:

Adding constraints

Using weight to control multiple constraints

Basic Constraints

Bounding constraints

Joint constraints

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