Adobe Director Basics

ADOBE DIRECTOR BASICS
3D: Controlling action
Mass and position properties
rigidBody.mass: a non-negative number. The default value of mass is 0.0, but rigidBody objects with a mass of zero
behave the same way as objects with a mass of 1.0. A rigidBody with a mass of zero will fall under the influence of
gravity, and will have a linearMomentum equal to its linearVelocity.
It is good practice to set the mass of all #dynamic rigidBody objects.
rigidBody.centerOfMass: a position vector, relative to the origin point of the model's geometry. The value by default
is vector(0, 0, 0). This defines the point around which the rigidBody will rotate.
rigidBody.position: a vector giving the current world position of the rigidBody. This will be the same as the
worldPosition of the model associated with the rigidBody.
rigidBody.orientation: a list containing a vector axis direction and a scalar angle. This will be the same as the
transform.axisAngle property of the model associated with the rigidBody.
If you change the mass of a moving rigidBody on the fly, the value of its linearVelocity and angularVelocity
will remain unchanged, but the value of its linearMomentum and angularMomentum properties will be adjusted
automatically.
To test these properties, launch the RigidBody.dir movie. Click the Fire Down zAxis button, to make a ball with a mass
of 1 strike the block. Check the value of linearVelocity and linearMomentum. Click the Reset button, alter the mass
of the block, and then click the Fire Down zAxis button again. Notice how the change affects both the relative
movements of the ball and the block, and how the linearVelocity and linearMomentum are related. Now try
moving the centerOfMass to an off-center position and try again.
Testing how mass and centerOfMass affect how a rigidBody behaves after a collision
Last updated 8/26/2011
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