Using the Update Command

This task shows you how to use the Update Positions command a very powerful tool which lets you keep the Assembly workbench and the Kinematics Simulator workbench synchronized. It means the modifications done are taken into account and the joints or constraints are respectively updated.
Note the synchronization between Assembly and Kinematics workbenches is relevant and complete only for joints with constraints.

Also read Replacing Curve Joint Specifications and Editing Curve Joint Specifications 
in the "Designing Higher Pair Joints " section.

When you need to re-import a mechanism, just click on the Update Positions icon, then select the imported mechanism you want to re-import as shown below:
Note: the behavior of this Update Positions command (described in the step-by-step scenario below) remains the same with non-imported mechanisms. 

For more detailed information on how to use the Import and Update commands, read Visualizing and Simulating in Sub-products and Managing Kinematics Data in Sub-products

What is taken into account ?
  • moving parts in the geometry area 
  • deleting or modifying assembly constraints
  • editing curve joints specifications 
Open the rods_with_joints.CATProduct  document.
  1. Move the Rod.2. and Rod.1 for this:

    •  Point to the compass manipulation handle
    • Drag and drop the compass onto the rod.4 in the geometry area
    • Move the rod.2.
  2. Reposition the 3D compass as it was.

  3. Click the Update Positions icon .
    The Update Mechanism dialog box is displayed:
    The 'Take current positions for rigid joints' option lets you take into account the new position.

  4. Click Ok to confirm your operation. The mechanism is updated and the part is back to its initial position.

    Now, move Rod.2 and Rod.1 in the same way .
  5. Click the Update positions icon .

  6. Select the Take current positions for rigid joints checkbox.

    This is what you obtain:
    Now simulate the mechanism. Please refer to Simulating With Commands.
    The current position has been kept for Rigid.2 (Rod.4, Rod.1)
    Now delete an assembly constraint.  
  7. If you need information about this particular constraint: double-click Coincidence.2 (Rod.3, Rod.4) in the specification tree to display the Constraint Definition dialog box.

  8. Right-click Coincidence.2 (Rod.3, Rod.4) in the specification tree. 

  9. Select Delete from the contextual menu displayed.

  10. Click the Update positions icon .
    The Update Mechanism dialog box appears.

  11. Click OK.The joints within the mechanism are updated.

    Revolute.1 (Rod.3, Rod.4) is converted into a Cylindrical joint (Cylindrical.1) as shown below: