Object Velocity & Acceleration

You can get Softimage to calculate an object's velocity and acceleration based on the object's animated transformations. You cannot modify the velocity and acceleration directly, but you can use the computed values in expressions, scripted operators, and elsewhere.

Understanding Motion Components

A moving object has speed or velocity. If it is changing speed, then it also has acceleration or deceleration (negative acceleration). For example, a car moving at a steady 100 km/h has a velocity of 100 but an acceleration of 0.

Velocity and acceleration can each be further divided into two types: linear and angular (or rotational). For example, a car that moves along a straight line has only a linear motion, whereas a ball that spins on the spot has only angular motion. A ball rolling on the floor has both types.

Calculating Velocity and Acceleration

By default, Softimage does not calculate velocity and acceleration to avoid unnecessary computations. However if you need to know these values for a specific object, you can activate them in the object's Global Transform property editor.

Note that you do not need to activate these values in order to read objects' velocity and acceleration in an ICE tree. ICE automatically calculates velocity and acceleration as needed.

To activate velocity and acceleration for an object

Select an object and open its Global Transform property editor.
On the Velocity/Acceleration tab, click Compute Vel/Acc.

The read-only Active option is selected to show that velocity and acceleration computations are performed for this object.

Removing Velocity and Acceleration

If you no longer need to know the velocity or acceleration of an object, there is no point continuing to perform those calculations because they are only slowing down your scene.

To stop computing velocity and acceleration for an object

Select the object and open its Global Transform property editor.
On the Velocity/Acceleration tab, click Remove Vel/Acc.

The read-only Active option is cleared to show that velocity and acceleration computations are no longer performed for this object.

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