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Part II: Working with Objects

After you’ve created the geometry for a light assembly, you can create an assembly with the Group ➪ Assembly ➪
Assemble menu command. This opens the Create Assembly dialog box, where you can name the assembly and
add a Luminaire object as the head object. Because the Luminaire object is the head object, you can see its
parameters in the Modify panel whenever the assembly is selected. Its parameters include a Dimmer value and a
Filter Color. These parameters are used only if they are wired to an actual light object included in the assembly.
Luminaire objects can be confusing because they don’t actually add light to an assembly. If you’re curious
about the Luminaire objects, you can find them in the Assembly Heads subcategory of the Helper category.
The benefit of the Luminaire helper object is that it can add to an assembly some simple parameters that are
accessible whenever the assembly is selected. These parameters work only if you wire them to the parame-
ters of the light object included in the assembly.
Cross-Ref
You can learn more about wiring parameters in Chapter 21, “Understanding Animation and Keyframes.” n

To wire Luminaire parameters to the light object’s parameters, select the assembly and open the Parameter
Wiring dialog box with the Animation ➪ Wire Parameters ➪ Parameter Wiring Dialog menu command (or
press the Alt+5 shortcut). In the left pane, locate and select the Dimmer parameter under the Object
(Luminaire) track. Locate and select the Multiplier parameter under the Object (Light) track, which is under
the Assembly01 track in the right pane. Click the one-way connection button in the center of the dialog box
that links the Dimmer to the Multiplier parameters, and click the Connect button. Next, wire the
FilterColor parameter to the light’s Color parameter.
After the assembly light is wired to the Luminaire parameters, you can use the Dimmer and Filter Color
parameters in the Modify panel whenever the assembly is selected.
Understanding Parent, Child,

and Root Relationships

Max uses several terms to describe the relationships between objects. A parent object is an object that con-
trols any secondary, or child, objects linked to it. A child object is an object that is linked to and controlled
by a parent. A parent object can have many children, but a child can have only one parent. Additionally, an
object can be both a parent and a child at the same time. Another way to say this is:
l Child objects are linked to parent objects.
l Moving a parent object moves its children with it.
l Child objects can move independently of their parents.
A hierarchy is the complete set of linked objects that includes these types of relationships. Ancestors are all
the parents above a child object. Descendants are all the children below a parent object. The root object is
the top parent object that has no parent and controls the entire hierarchy.
Each hierarchy can have several branches or subtrees. Any parent with two or more children represents the
start of a new branch.

Cross-Ref
The default hierarchies established using the Link tool are referred to as forward-kinematics systems, in which
control moves forward down the hierarchy from parent to child. In forward-kinematics systems, the child has no
control over the parent. An inverse kinematics system (covered in Chapter 38, “Working with Inverse
Kinematics”) enables child objects to control their parents. n

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