8

Sliding and Rotational Jo ints Rollouts (HD Solver) 479
axis. If you turn on Limited, specify limit
values in t he From and To fields. When
setting limits, the object transforms to the
position or rotation defined by the From or
To field. When you exit the field or release
the spinner, the object returns to its original
position. You can also view joint limits in
the viewport by pressing and holding the
mousebuttonontheFromorTolabelofa
limit field. The object wi ll move or rotate to
thelimitvalueuntilyoureleasethemouse
button.
Inter face
Sliding/Rotational Joints rollouts
The Sliding Joints rollout a nd Rotational Joints
rollout contain similar controls for position and
rotation,respectively.Also,eachrolloutcontains
identical group boxes for control of the X, Y, and Z
axes.
X/Y/Z Axis groups
Active—Activatesanaxis(X/Y/Z).Allowsthe
selectedobjecttoslideonorrotateaboutthe
activated axis.
Limited—Limits the range of motion or rotation
allowedonanactiveaxis.Useinconjunctionwith
the From and To spinners. Most joints are limited
in their range of motion along an active axis. F or
example,apistonslidesonlywithinthelengthof
its cylinder.
Ease—Causes a joint to resist motion as it
approaches its From and To limits. Simulates an
organic joint, or worn mechanical joint, moving or
rotatingfreelyinthemiddleofitsrangeofmotion
but moving less f reely at the extremes of its range.
From a nd To S pinner s—Determine for position
and rotation limits. Use in conjunction with the
Limited function.
Spring B ack —ActivatesSpringBack.Eachjointhas
a rest position. As the joint moves further from the
rest position, an increasingly larger force pulls the
joint back to its rest position, like a spring.
Spr ing B ack (spinner)—Sets the rest position
for the joint. For rotational joints, this is the
orientation of the joint in degrees; for sliding
joints, it’s the position in units. Adjusting this is
similar to adjusting the From/To spinners. You
see the orientation/position while performing the
adjustment, but when you release the spinner the
object returns to its previous state.
If you’re using the HD Solver, you must turn on
Show Initial State (Motion panel > IK Controller
Parameters rollout) to see the effect on the
geometry during the adjustment .
Spr ing Tension—Sets the strength of the "spr ing."
Higher values cause the spring to pull harder as
the joint moves further from its rest p osition. A
setting of 0 turns off the spring; very high settings
can turn the joint into a limit because you can
reach the point where the spring is too strong to
allow the joint to move past a cert ain point.
Dampi ng—Applies resistance over a joint’s full
range of motion or rotation. Simulates the natural
effect of joint friction or inert ia. As a joint
corrodes, dries out, or is put under a heavy load, it
resists motion along its active axes.