Mechanism Design and Mechanism Dynamics > Mechanism Dynamics > Initial Conditions > About Initial Conditions
About Initial Conditions
Initial conditions are position and velocity options you set when performing a dynamic analysis. Initial condition definition is available only if you have a Mechanism Dynamics license.
Click the relevant button under Velocity Conditions in the Initial Condition Definition dialog box to specify the following initial conditions:
Position Initial Condition—Makes sure an analysis starts from a specific position. By default, each analysis starts with the mechanism displayed as the current screen position–the current orientation of the bodies as you see them on the screen. You can use initial conditions to establish a consistent starting configuration for each analysis.
The software uses a snapshot to reference initial position. The snapshot captures the configuration of existing locked bodies and geometric constraints to define position constraints.
Velocity Initial Condition—Starts the analysis at a particular velocity. You can define point, motion axis, angular, and tangential slot velocity settings.
For example, if you are modeling a car, you might want–at the start of the analysis–to analyze it moving at 65 mph. Another example of a velocity initial condition would be the body angular velocity in deg/sec of a door closing.
Before defining your initial conditions, you may want to review some tips on how to use initial conditions effectively.
Initial Conditions from Playbacks
When you need to create multiple analysis definitions to investigate motion of a mechanism with different configurations, you can use a playback from a previous analysis as an initial condition. The velocities and positions captured in the playback become the initial conditions for the next analysis. This allows you to create a chain of analyses where each one can have different constraints, connections, motors, springs, dampers, etc.