2009

Use of the Limit controller makes it faster to set up and create animation. It
eliminates the need for expressions or scripts to do the same thing, this
improving the ease with which you can set up automation in hierarchies and
rigs, creating effects such as avoiding collision, FK joint limits, etc.
For example, a Technical Director might want to assign limits to float values
that animators will adjust to make posing easier, enforce standards, or prevent
inconsistencies and mistakes. A TD could use limits for:
■ light intensity
■ finger rotation
■ position extents for sliding drawers
■ camera field-of-view
■ limiting patch resolution to that supported by the game engine
Character riggers can use limits to create complex relationships or shortcuts
in rigs. Examples include:
■ Wire wrist-twist bones to the rotation of the hand, but limit the rotation
of the wrist-twist or hand to stop short of any flipping that might occur.
■ Prevent unnatural translation of a spline IK helper by causing limit values
for its local position tracks to react to the angle or distance of the helper
from surrounding helpers.
■ React to when IK is disabled, and match the limits of the solver in FK.
■ Limit the position of the IK chain swivel-angle target for the knee so that
it can never go behind the character. That is, the target is linked to
character’s root.
Use Cases
Following is a brief list of examples of specific uses for the Limit controller:
■ Select the Y Rotation tracks of all finger bones in a character's hands and
assign a Limit controller. Use Set Key mode to pose the fingers at the
extremes of their ranges of motion and then use the
right-click menu on
page 3192 > Set Upper/Lower Limit commands to limit the fingers' motion.
NOTE Limits are included for Set Key via the Other category.
3182 | Chapter 15 Animation