About Mechanisms

A mechanism is an assembly of bodies moving relative to each other and according to predefined constraints defined by joints or other motion elements. To study the motion of an existing physical product and its associated engineering connections, you first need to create a mechanism from the physical product.

This page discusses:

Mechanism Creation

You can create a mechanism based on an existing assembly of products, or with no associated product.

If you create a mechanism from an active product, a body is generated for each product, and a joint for each engineering connection enforced in the mechanism. Markers are created automatically on the bodies to define the position and orientation of the joints.

In the tree, bodies and joints are created at the same location as their corresponding products or engineering connections.

The elements from the product assembly are associated to the mechanism elements. If you modify a product or engineering connection, the bodies and joints are updated accordingly following the update of the mechanism.

You can create a mechanism using one or more engineering connections in a product. You can create multiple mechanisms under the same product by selecting either some or all of the engineering connections in the product.

Note: You can only apply motion to a mechanism. It is not possible to apply motion to a product.

If you create a mechanism as a stand-alone entity, you can decide to define each body and joint independently. A body can reference a product as a geometry element for the product to move according to the body.

If you modify the assembly, you must update the mechanism. For more information, see About Mechanism Update.

Mechanism Components

In the tree, mechanisms appear under the Mechanism node of the product. A mechanism includes specific components (such as bodies, joints, or drivers), and unique mechanism features (such as gravity).

Active Mechanism

To create a mechanism under a product, you must define the product as the active product. You can create several mechanisms under the same product. The active mechanism of an active product is considered as the current mechanism.

The name of the active mechanism is underlined in the tree.

By default:

  • The active product is the root product.
  • The active mechanism is the first mechanism under the active product.

To define another mechanism as the active mechanism, right-click the mechanism in the tree and set it as current.

Set a mechanism as the active mechanism to:

  • Visualize the mechanism.
  • Edit the mechanism.
  • Create new elements in the mechanism.
  • Visualize the kinematic motion of the mechanism (mechanism motion without applied or external forces).
  • Compute the dynamic simulation of the mechanism by considering the applied and external forces.