Mover Constraints

The physics engine includes the following Constraints that apply force or torque to move one or more assemblies. In addition, various mechanical constraints are available which behave as conceptual mechanical connections, including hinges, springs, ropes, and more.

LinearVelocity applies force on an assembly to maintain a constant velocity along a 3D vector, line, or 2D plane
AngularVelocity applies torque on an assembly to maintain a constant angular velocity
AlignPosition applies force to move two attachments together, or to move one attachment to a goal position
AlignOrientation applies torque to align two attachments, or to align one attachment with a goal orientation
VectorForce applies constant linear force on an assembly
Torque applies constant torque on an assembly from its center of mass
LineForce applies force along the theoretical line connecting its two attachments

Constraint Visualization

To accurately visualize constraints in Studio, you can use the following options from the Model tab:

Constraints tools indicated in Model tab

Show Welds — Show WeldConstraints, separately from the visualization of other constraints.

Constraint Details — Show complete visual details of non-weld constraints.

Scale — Relative scale of visualizations.

Creating Constraints

Mover constraints typically connect one or two Attachments or Bones. When connected to Bones, the constraint will use their animated position and orientation.

To create a mover constraint, you can use either the Create tool or the Explorer window.

  1. In the Model tab, access the Create button's picker menu and select the desired constraint type, for example Angular Velocity.

    Constraint picker indicated in Studio toolbar
  2. In the 3D viewport, hover over any Part or MeshPart and click to add a new Attachment to the part at the visualized point. Alternatively, hover over and click an existing Attachment or Bone to use it for the constraint.

  3. Some mover constraints utilize or support a secondary attachment in their functionality, so the tool might prompt you to repeat the previous step on another Part, MeshPart, or Attachment, or Bone.

    AngularVelocity using one attachment
    AngularVelocity using one attachment
    AlignPosition using two attachments
    AlignPosition using two attachments

Physical Simulation

To simulate physics while moving or rotating parts, you can switch to Physical mode in the Model tab, effectively forcing parts to obey physical limitations. For example, if you drag one part around the scene and it collides with another part, it will physically push that part out of the way.