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740 Chapter 13: reactor
3.
ChangetheCone>MinandMaxsettings.
When displayed, the cone remains symmetrical
and is rotated about the plane normal by the
average offset of Min and Max. For example, if
Min=-10.0 and Max=20.0, the average offset
is (-10+20)*0.5=5 with a cone angle of 15. In
effect,wehavea15-degreesymmetricalcone
[-15, 15] rotated by 5 degrees, resulting in
limits of [–10, 20]. If the plane normal is not
at 90 degrees to the twist axis, non-intuitive
cone rotations can result. The rotation of the
tw ist axis for the attached object is limited to
thevolumeofthiscone.Youcanviewthecone
on its own by ensuring that only the Show
Cone option in the Properties rollout > Display
group is on.
4. You can also try changing the Plane > Min and
Max settings. These are limited between [-90,
0] and [0,90] respectively. Tak ing the Min and
Max limits and sweeping those angles around
the plane normal creates cones. The rotation of
the attached object is then limited to within the
region between the plane and these cones.
You c an also rotate the plane independent of
the twist axis. To display the plane limits, turn
on Display rollout Show Plane Limits.
5. BycombiningConeandPlanelimitsyou
generate valid rotational regions for the child
object relative to the parent object. This is the
region represented by the Show Volume option.
Note: Cone and plane limits limit the movement
independently. As a result, it is po ssible to
have ineffective plane limits, where the cones
generated by the plane limits do not intersect
theconegeneratedbytheconelimits.Usethe
planelimitstoreducethelevelofmovement
provided by the cone.
To change the Twist limits:
1.
Select the Rag Doll helper object and open the
Properties rollout.
2. The Twist settings limit the rotation of t he child
object about the twist axis relative to the parent
object.Tofixthetwistofoneobjectrelativeto
the other, set the twist limits to [0,0].
3. Display the Twist limits by turning on Display
rollout > Show Twist.
For a detailed explanation of how to define these
limits, see Defining Rag Doll Limits (page 2–743).