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754 Chapter 13: reactor
the parent around the x, y, and z axes - for each
axis there is a minimum (counter clockwise) and
maximum (clockwise) limit. You can use the
check bo x es to switch on or off the limit displays in
the viewpor t.
Length (Sti ff S pri ngs only)—The distance t hat
reactor should maintain b etween the constraint
attachment points.
Set—Sets Length to the c urrent distance between
the attachment points.
Breakable group
Breakable—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 Constraints
(page 2–735).
Display group
Size—Letsyouchangethesizeoftheconstraint
limit display in the viewport.
Reset Default Values—Returns the constraint’s
parameters to their default values.
Prismatic Constraint
Create panel > Helpers > reactor > Prismatic
Menu bar > reactor > Create Object > Prismatic Constraint
reactor toolbar > Create Prismatic Constraint button
The Prismatic constraint serves as a constraint
between two rigid b odies, or a rigid body and the
world, that allows its bodies to move relative to
each other along one axis only. Rotations, as well
as the remaining two translation axes, are fixed.
For example, you could use a Prismatic constraint
when creating a forklift truck.
A Prismatic constraint is s imulated if it has the
correct number of rig id bodies attached and is
included in a valid Constraint Solver (page 2–736).
When not selected, an invalid prismatic constraint
is red in the viewport.
Procedures
To create a Prismatic constraint:
• Chooseoneoftheaboveoptions,andthenclick
in any viewport to add the Prismatic constraint.
Note: The icon’s position has no effect on the
constraint’s behavior.
To attach objects to the pr ismatic constr aint:
1.
Create the Prismatic constraint and the objects
to connect using it.
2. On the constraint’s Properties rollout, click
the Chi ld pick button and then, in one of t he
viewports, select the object to use as t he child.
This attaches the constraint to the body at the
body’s pivot point. The constraint’s sliding axis
is alig ned to the Z a xis of the object.
3. If you do not want to assign a second b ody to
the prismatic constraint, turn off the Parent
check box, if necessary.
4. If the constraint is to be two-bodied, make sure
Parent is on and then u se the Parent pick button
to set the parent for the constraint.
To create the constra int a nd a ttach objects in a single
step:
•SeetheScripts (page 2–817) topic.
To change the Prismatic constraint positions and
rotations for the bodies:
1.
With the constraint selected, open the Modif y
panel.
2. In the modifier stack open the constraint’s
sub-object list.