8

414 Chapter 12: Animation
Consider a sphere with a radius of 20 units and a
linked child object:
1. Use Uniform Scale to scale the sphere to 200%.
The sphere and its child become twice as big.
Scale Tra nsform Type-In reports an Absolute
Local Sc ale of 200% and the object’s creation
parameters report a radius of 20 u nits. The true
radius of the sphere is 200% of 20 units, or 40
units.
2. Select the sphere and click Reset Scale. The
sphere and its child remain the same size.
Here’s w hat has happened:
The 200% scale has been absorbed by the
sphere as its origina l state. The sphere has a
true radius of 40 units, Creation P arameters
report a radius of 20 units, and absolute local
scale is 100%.
The sphere’s child object accepts a local scale of
200% so it does not change in size.
Resetting the sc ale of an object c an lead to
confusion because the object’s t rue size, absolute
local scale, and creation parameters no longer
match up.
Using the R eset Transform Utility
You can also reset the orientation and scale of an
object by clicking
Reset XForm (page 1–418) on
the
Utilities panel (page 3–821) .ResetXForm
takes the rotation and scale transforms of an object
andplacestheminanXFormmodifieronthe
modifier stack.
Considerthesamesphereasbeforewitharadius
of 20 units and a linked child object:
1. Use Uniform Scale to scale the sphere to 200%.
Thesphereanditschildbecometwiceas
big. The Scale Transform Type-In reports an
Absolute Loc al scale of 200% and Creation
Parameters report a radius of 20 units. The true
radius of the sphere is 200% of 20 units, or 40
units.
2. SelectthesphereandclickResetXForm.The
sphere remains the same size but its child
reverts to its or iginal size and position. Here’s
what has happened:
The 200% scale has been placed in an XForm
modifier on the sphere’s modifier stack. The
sphere has a true radius of 40 units, Creation
Parameters report a radius of 20 units, and
absolute local scale is 100%.
The sphere’s child object now sees only the
100% local scale so it reverts to its orig inal size
and position.
Locki ng Obj ect Tra nsfor ms
You can lock an object’s ability to move, rotate,
or scale about any of its local axes by selecting
objects a nd then setting options on the
Locks
(page 2–482)
rollout of the Hierarchy panel.
Enabling a nd disabling Local transform axes is
also referred to as setting degrees of freedom
(DoF)foranobject.Ifanaxisisenabled,anobject
is f ree to t r ansform about t hat Local axis.
The Locks rollout contains three groups: one each
for Mov e, Rotate, and Scale. Each group contains
three options, one each for the X, Y, and Z Local
axes of the selected objects.
• When turned on, the objects cannot be
transformed about the selected Local axes when
you directly use one of the transform tools.
Objects can stil l be transformed by other means
such as b eing a child of a transformed parent
object or being part of an inverse kinematics
chain.
• When turned off, objects can be freely
transformed about the unlocked Lo cal axes.