CONSTRAINT

Position Limits

 

The Constraint->Position Limits command in the Actor and Motion modules sets a constraint on the range of position of one or more objects relative either to another object or to the global (world) origin. This means that objects cannot be translated to a position farther away from the constraining object than a specified distance. A damping effect can also be set, adding resistance to the object's movement so that abrupt stops are avoided.

For more information about animating using constraints, see the Constraints section of the Animating User's Guide.

 

Procedure

  1. Select the object(s) to be constrained.
  2. Choose the Constraint->Position Limits command.

    The Position Limits dialogue box is displayed.

  3. Set the Limit type.

    Note:

    When setting the Limit type's MIN and MAX translation values for each axis, select its check box first, then type the desired values into the corresponding text box. Only the values for selected check boxes are applied.

  4. Select the Reference point of the constraining area.
  5. Set the Damping Width and Damping Strength.
  6. Click Ok to confirm the settings and exit the dialogue box.
  7. If another object is to act as a constraint, pick the object following the mouse button instructions in the status bar.

    The constraining object flashes red. The constrained object(s) adjusts its position according to the specified values, so that its centre is either the specified distance from the centre of the constraining object or from the centre of the world.

  8. Select and translate the constrained object as desired.

The constrained object does not move further from the constraining object than the specified values.

 

Parameters

Limit Type

Sets the shape and size of area to which the constrained object is limited. By default, the constraining area shape is Box.

Sphere

Establishes the constraining area as sphere-shaped.

Radius

Sets the distance, in units, that the centre of a constrained object can be translated from either the centre of the constraining object or the centre of the world (origin). By default, the radius is set to 5.0 units.

Box

Establishes the constraining area as box-shaped.

MIN and MAX Limits

MIN and MAX values are expressed in SOFTIMAGE units. They represent the minimum and maximum distance that the centre of a constrained object can be translated, relative to either the centre of the constraining object or the centre of the world (origin).

For example, if the MIN and MAX position limits are set to -10 and 10 units for all axes, you can translate the constrained object in any axis until its centre is within 10 units from the constraining object's centre (Damping may affect the actual distance that the object can move).

Reference

Sets the reference point for the constraining area at either the centre of a constraining object or the centre of the world (origin).

By default, the reference point is set to Object.

Damping

The Damping options set a degree of resistance to the movement of a constrained object as it approaches the outer limits of the constraining area. These options set the strength of the resistance and distance from the reference point that damping begins to take effect.

Damping Width

Sets the distance from the reference point that damping begins to take effect. The value is expressed in SOFTIMAGE units.

For example, if the damping width is set to 2 units, and the constraining area is sphere-shaped with a radius of 10 units, the object can be translated 8 units from the reference point before damping takes effect.

By default, Damping Width is set to 0.

Damping Strength

Sets the strength of the damping effect. A value of 0 indicates no visible resistance to the movement of the object as it approaches the outer limits of its constraining area, while a value of 1.0 indicates very strong resistance. The larger the value specified, the stiffer the damping is.

By default, the Damping Strength is set at 0.5 units.

 

Last updated 03-apr-1998