About Locking and Unlocking Commands

Locking and unlocking commands for partially defined mechanisms allows you to drive the mechanism's animation with more accuracy. By selecting one mechanism's configuration over another, you can animate the mechanism's motion you envision. Locking a command ensures that the value assigned to a specific command is constant throughout the animation.

See Also
Locking and Unlocking Commands
About the Mechanism Manager
Animating Mechanisms

Consider the following cases.

Fully Defined Mechanism
For a mechanism to be simulated, it must be fully defined. The mechanism's setup must be complete. The engineering connections enforced in the mechanism are specified, as well as the degrees of freedom controlled by the mechanism commands.

The mechanism manager indicates when enough specifications are defined. In the Mechanism Player dialog box , a fully defined mechanism is identified by the color-coded status icon .

If you modify the value of a command using the slider or the value box, the values assigned to the other commands in the mechanism are not modified.

Consider the following fully defined mechanism:

Command Command value
Command.1 0deg
Command.2 -36deg
Command.3 -108deg
Command.4 0deg
Command.5 0deg

If you modify the value of Command .1 from 0deg to 54deg, the values assigned to the other commands are not modified:



Command Command value
Command.1 54deg
Command.2 -36deg
Command.3 -108deg
Command.4 0deg
Command.5 0deg

Partially Defined Mechanism
A mechanism is partially defined if:
  • it is underconstrained
  • it includes interdependent commands
  • it includes a combination of both.
A partially defined mechanism can be simulated, but locking commands ensures that the mechanism's animation is not interrupted.

A partially defined mechanism is identified by the color-coded status icon .

If you modify the value of a command using the slider or the value box, then the values assigned to the other commands of the mechanism may be modified if certain degrees of freedom are not specified.

If you lock the values of specific commands, the values remain constant during the animation. The overall motion of the mechanism can be fully simulated.

Consider the following partially defined mechanism:

Command Command value
Damper 1 cylindrical cmd 31.5mm
Damper 2 cylindrical cmd 0mm

If you modify the value of the Damper 1 cylindrical cmd from 31.5mm to 20mm, the value assigned to the Damper 2 cylindrical cmd is modified:

Command Command value
Damper 1 cylindrical cmd 20mm
Damper 2 cylindrical cmd 7.5mm

Now, click next to the Damper 2 cylindrical cmd value. The value is locked . If you modify the value of the Damper 1 cylindrical cmd, the value of the Damper 2 cylindrical cmd remains constant during the animation.