8

376 Chapter 12: Animation
• LookAt constraint (page 2–388) constrains an
object’s orientation so that it’s always looking
at another object
•
Orientation constraint (page 2–391) causes the
rotation of the constrained object to follow the
rotation of another object
Tip: You can use Schemat ic View to see all the
Constraint relationships in a scene.
Using Constr ai nts wi th B ones
Constraints can be applied to bones as long as an
IK controller is not controlling the bones. If the
bones have an assigned IK controller, you can only
constrain the root of the hierarchy or chain.
Attachment Constrai nt
Animation menu > Constraints > Attachment Constraint
Attachment constraints keep the cylinders on the surface.
TheAttachmentconstraintisapositionconstraint
that attaches an object’s position to a face on
anotherobject(thetargetobjectdoesn’thavetobe
amesh,butmustbeconvertibletoamesh).
By key ing different attachments over time, you can
animate the position of an object over the irregular
surface of another object, even if that surface is
changing over time.
Procedures
Exa mple: To attach a cone to a bending cylinder:
1.
In the Perspective viewport, create a cy linder
with a radius of 20,aheightof30,and10 height
segments.
2. In the Perspective viewport, create a cone with a
radius 1 of 15,aradius2of5,andaheightof30.
3. Select the cylinder, apply a B end modifier, and
set the bend ang le to -70 degrees.
4. Tur n on Auto Ke y, move to frame 100, and set
the bend angle to 70 degrees.
Thecylinderbendsfromonedirectiontothe
otherover100frames.
5. Tu r n off Auto Ke y.
Exa mple continued: To a ssign the Atta chment
constrai nt and a djust the cone:
1.
Select the cone.
2. OntheMotionpanel,opentheAssign
Controller rollout, click the Position track, click
Assign Controller, and choose Attachment.
Theconemovestotheoriginofthescene,and
the Attachment Parameters rollout is displayed.
3. Click the Pick object, and then click the
cylinder.
Thenameofthecylinderisdisplayedabovethe
Pick Object button.
Go to frame 0. Arc Rotate the Perspective
view por t so you can see the top surface of the
cylinder.
4. Click Set Position, and click and drag over the
faces on the top surface of the cylinder.