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752 Chapter 13: reactor
2.
IntheConstraintTypegroup,chooseLimited.
By default, the child body can rotate a total of 90
degrees around each axis relative to the parent
during the simulation: 45 degrees clockwise
and 45 degrees counterclockwise.
3. You can then choose which limits to display
around the Parent Space constraint axis by
turning on each one’s check box.
4. If you then change the limits, the limit display
updatestoreflectyourchangestohelpyou
choose appropriate values. Upon simulation
you can see that the rotation between the
objects has been limited.
5. You can also change the orientation of the axis
to be limited by rotating the Child Space and
Parent Space sub-objects.
To create a S tif f Spr ing constraint:
1.
With a Point-Point constraint selected, open
the Properties rollout.
2. IntheConstraintTypegroup,chooseStiff
Spring.
3. Yo u c a n n o w s p e c i f y a L e n g t h v a l u e f o r t h e
stiff spring. The default is 0.0: the same as a
Point-Point constraint.
During the simulation, reactor works to
maintain this distance between the constrained
objects’ attachment points. To use the cur rent
distance between the attachment points as the
length, click the Set button.
Interfa ce
Modifier Stack
Parent S p a ce—At t his sub-object level, you can
select and move the constraint attachment point in
the parent body’s local space. When you assign a
parent object to the constraint, the Parent Space
attachment point is set to the child object’s pivot
point. If you alter the position of t he Parent Space
attachment point, it maintains its new position
relative to the parent during the simulation. If
the constraint is single-bodied, the Parent Space’s
position represents the point in the world where
the constraint is attached.
Child Space—At this sub-object level, you can
select and move the constraint attachment point
in the child body’s local space. When you assign
a child body to the constraint, the Child Space
attachment point is set to the child object’s pivot
point. If you alter the position of the Child Space
attachment point, it maintains its new position
relativetothechildduringthesimulation.