9

Car-Wheel Constraint 757
You assign the parent object by clicking this button
and then selecting a r igid body from any view port.
Thereafter the button displays the name of the
parent bo dy.
Child—Displaysthenameofthesecondrigidbody
attached to the constraint. You assign the child
object by clicking this button an d then selecting a
rigid body from any viewport.
Align Spaces To—Use these options to align the
bodies’ local constraint spaces. You can find
out more about each option in Working With
Constraint Spaces (page 2–726).
Lock Rel a ti v e Tr a ns fo r m—When on, the relative
transform b etween the child and parent constraint
spaces is locked: If you move either space i n the
viewport, the other space moves and rotates along
with it, and vice-versa.
Strength group
Strength/Tau—Govern the impulses applied to
the constraint’s bodies in order to maintain the
constraint, and so how strongly the constraint
works to restr ic t their movement. You can find out
more about these parameters in Strength and Tau
(page 2–735).
Limited group
Limited—When on, limits the movement of the
child object along the sliding axis; the child object
can move relative to the parent only within the
range specified by the Min Limit and Max Limit
values.YoucanalsospecifyaFrictionvaluefora
limited prismatic constraint.
Min Limit—The minimum distance the constraint
allows b etween the two spaces. For example, if Min
Limit is –5.0 then the child bo dy then the child
objectcannotmovemorethan5unitsbackwards
relative to the parent along the sliding axis.
Max Limit—The m ax imum distance the constraint
allows b e tween the two spaces. For example, if
Max Limit is 5, then the child object will not b e
able to move more than 5 units forward relative to
theparentalongtheslidingaxis.
Fr iction —The level of friction applied to the objects
as they t ry to move along the sliding axis. It is
applied only to limited Prismatic constraints.
Breakable group
B r ea kab l e—When on, the constraint is breakable.
If its breakable limits are exceeded during
simulation, it ceases to exert impulses on the
attached objects. You can find out more about
breakable constraints in Breakable Constrain ts
(page 2–735).
Display group
Size—Lets you change the size of the constraint
space display in the viewport.
Reset Default Values—Returns the constraint’s
parameters to their default values.
Car-Wheel Con strain t
Create panel > Helpers > reactor > Carwheel
Menubar>reactor>CreateObject>Car-Wheel
Constraint
reactor toolbar > Create Car-Wheel Constraint button
You can use this constraint to attach a wheel to
another object; for instance, a car chassis. You
canalsoconstrainawheeltoapositioninworld
space.Duringthesimulation,thewheelobjectis
free to rotate around a spin axis defined in each
object’s space. Linear motion is al lowed for the
wheelalongasuspensionaxis. Youcanalsoadd
limits to the wheel’s movement along this axis. The
constraint’s child body always acts as the wheel,
while the parent acts as the chassis.