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96 Chapter 3: Selecting Objects
When you create a group, all of its member objects
are rig idly linked to an invisible dummy object.
The group object uses the pivot point and the
local transform coordinate system of this dummy
object.
Groups can be nested. That is, groups can contain
other groups, up to any level.
Transforming and Modifying a Group
You c an t r ansform or m odify a group as if it were a
single object, and you can animate the transforms
and the modifiers.
When you apply a modifier to the group, this
applies an instance of the modifier to each object
in the group. A g rouped object retains its modifier
instance, even if you later remove it from the
group.
When you apply a transform to the group, on the
other hand, this applies only to the group as a
whole. More precisely, 3ds Max applies transforms
to the dummy object that represents t he group.
You can tr ansform and animate individual objects
within a g roup independently from the group
itself. However, when you transform the group
itself, the transform affects all grouped objects
equally. The group transform is uniformly added
to objects that have independent motions. An
analogy is a cage of birds, each flying around on
itsown,whilethecageitselfisbeingmoved. In
thecaseofgroups,the"cage"(thedummyobject)
expandstosurroundallobjectsinthegroup,
wherever the objects’ independent transforms take
them.
Accessing Objects in a Gr oup
You can open and close groups to access the
individual objects contained in them without
dissolving the group. These commands maintain
the integrity of the group.
•
Open (page 1–102) :Temporarilyopensthe
group so that you can access its member
objects. While a group is open, y o u can treat
the objects (or nested g roups) as individuals.
You can transform them, apply modifiers, and
accesstheirmodifierstacks.
•
Close (page 1–102) : Restores t he g roup when
you’re finished working with the individual
objects.
Dissolving Groups
You can permanently dissolve g roups by either
ungrouping or exploding them. Both commands
dissolve groups, but to different levels.
•
Ungroup (page 1–103) :Goesoneleveldeepin
the group hierarchy. It separates the cur rent
group into its component objects (or groups),
and deletes the group dummy object.
•
Explode (page 1–103) :SimilartoUngroup,
butdissolvesallnestedgroupsaswell,leaving
independent objects.
When you Ungroup or Explode a group, the
objects within the group lose all group transforms
not on the current frame. However, objects retain
any individual animation.
To transform or modify the objects within a group,
youmustfirstremovethemfromthegroup,either
temporarily or per manently. The Open command
lets you do this.
Comparing Groups with Other Selection
Methods
Compared to the other metho d s you can use to
combine objects in 3ds Max, grouping is more
permanent than selection sets, but less permanent
than attaching objects.
•
Selection sets (page 1–64) :Formatemporary
collection of objects to which you apply the
current commands. As soon as you select
another object, the s election set is gone.