Creating 3D Contacts

You can create kinematics and dynamics contacts between bodies of a mechanism by selecting the bodies that come into contact, adjusting their mesh, and specifying the contact properties.

Before you begin:
  • Create a mechanism.
  • Create bodies with a geometry assigned.
See Also
About 3D Contacts
  1. From the Mechanism section of the action bar, click 3D Contact .
    A 3D contact element is created in the tree, under the Contacts node of the active mechanism .
  2. In the Define Contact section, select one of the following options to determine which bodies are coming into contact:
    OptionDescription
    Within one list Lists the bodies from the mechanism that come into contact.
    Note: Use this option if all bodies from the mechanism are coming into contact or if you are uncertain which bodies are to come into contact.
    Between two lists Lists two groups of bodies that come into contact with one another.
    Note: Use this option if you know which bodies are to come into contact.

    Note: All the volume geometries of the selected bodies are used for contact.

    Depending on your selection, one or two contact lists appear.
  3. If you click Within one list, select at least two bodies from the current mechanism.
    • Each body is paired with the other bodies from the list.
    • The Number of contact pairs is computed automatically.
      Note: The computed number equals the number of possible combinations between bodies from the Contact list.
  4. If you click Between two lists, in the Contact list 1 and Contact list 2, select one or more bodies from the current mechanism.
    • Every body from Contact list 1 is paired with every body from Contact list 2.
      Note: Bodies from the same list are not paired with one another.
    • The Number of contact pairs is computed automatically.
      Note: The computed number equals the number of contact pairs between every body from Contact list 1 and every body from Contact list 2.
  5. In the Mesh section, specify the mesh density of the contacting surfaces. To do so:
    • Enter a value in the Mesh density field.
    • Move the slider to adjust the mesh density of the contacting surfaces.

    The default value for the mesh density is 35. You can specify a value between 0 (coarse mesh) and 100 (fine mesh).

  6. In the Contact Properties section, enter a value for each of the following properties:
    1. In the Restitution coefficient field, enter a value between 0 and 1.
    2. In the Sliding friction coefficient field, enter a value higher than or equal to 0.

      Recommendation: Specify a value between 0 and 0.5.

    3. In the Stiffness scaling field, enter a value between 0 and 1.

      Note:

      A value of 1 corresponds to a point contact with steel-steel material pairing.

      Recommendation: You can specify a value below or above 1 in the following situations:
      • For point contacts or contacts between bodies with very soft materials, you can specify a value above 1 to make the contact harder.
      • For conformal contact situations (large contact areas) and hard materials, such as steel-steel, you can specify a value below 1 to make the contact softer.

  7. Click .