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Deformable Bodies 777
<<—
Moves all the pairs in the Do Not Store list to
the Store list.
OK —Closes the dialog, saving any changes.
Cancel—Closes the dialog without saving your
changes.
Defor mable B odies
Yo u c a n u s e rigid bodies (page 2–716) in reactor to
model any real-world object whose shape doesn’t
change over time. However, what if you want to
simulate an object whose geometry does change
over the course of the simulation, such as a cloak,
hair, foam bricks, or perhaps a slithering tentacle?
reactor allows you to model these with a second
category of objects, called deformable bodies.
The geometry (vertices) of deformable bodies
can change over time, driven either by reactor
during the simulation or by existing animation in
3dsMax,allowingtheobjectstobend,flex,and
stretch while affecting and being affected by the
rest of objects in the world simulation.
Impor tant: TheHavok3enginedoesnotsupport
deformable bodies in reactor; you can use these only
with the Havok 1 engine.
In addition to creating entirely deformable objects,
you can combine deformable bodies with rigid
bodies, for instance to add secondary motion to
a simulated character. Secondary motion could
include swirling clothing, wobbling flesh, or a
swinging tail. Deformable objects are also useful
for en vironmental effects such as swinging ropes
and chains, cur t ains, and flags with dynamic wind.
Generally, you create a deformable body in reactor
by first creating a mesh or spline that models the
object’s basic shape, and then applying a special
modifier.Youcanthenspecifyadditionalphysical
properties for the object. reactor includes four
main types of deformable bodies, each of which is
dealt with in its own section:
• Cloth (page 2–778),adeformable
two-dimensional triangular mesh
• Soft Body (page 2–783),adeformable
three-dimensional closed triang ular mesh
• Rope (page 2–789),adeformable
one-dimensional chain of vertices.
• Deforming Mesh (page 2–793),adeformable
mesh whose vert ices have already b een
animated, for instance the skin on a character
rig.
As with rigid bodies, you must add deformable
bodiestoacollectioninordertobeaddedtothe
simulation. Each deformable body type has its
own corresponding collection type.
Also like rigid bodies, you can constrain the
possible movement of deformable bodies: see
Constraining Deformable Bodies (page 2–795).
Note: Deformablebodiesaremorecomplexthan
rigid bodies (page 2–716), so reactor requires more
time to simulate them.
Wor k ing with Deformable-B ody Ver tices
reactorincludesseveraltoolsforworkingwith
individual vertices in deformable bodies. The
topics covering these are:
• Fixing Vertices in World Space (page 2–796)
• Keyframing Vert ices (page 2–797)
• Attaching Vertices to a Rigid B ody (page 2–798)
• Attaching Ver tices to Deforming Meshes (Skin)
(page 2–799)
• Soft Selection (page 2–800)