Building Assemblies

At the bottom of the Group menu is a menu item called Assembly with a submenu that looks frightfully similar to the Group menu. The difference between a group and an assembly is that an assembly can include a light object with a Luminaire helper object as its head. This enables you to build light fixtures where the light is actually grouped (or assembled) with the light stand objects. Once built, you can control the light by selecting and moving the light assembly.

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, shown in Figure 10.2, where you can name the assembly and add a Luminaire object as the head object.

Figure 10.2: The Create Assembly dialog box lets you choose a light 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.

Note 

If you apply a modifier to an assembly, it affects only the Luminaire head object, so Parametric Deformation modifiers like Twist have no effect. If you open the assembly, you can select and apply a modifier to an individual assembly object.

Adding lights to assemblies

If you know that your light characteristics aren't going to change, then set up the parameters for your light object before you build the assembly and the light object will provide constant light. If you ever need to change a light setting, just open the assembly with the Group Assembly Open menu command. Then select the light object, and its parameters appear in the Modify panel. After you've changed the light parameters, close the assembly again with the Group Assembly Close menu command.

Note 

Adding a light object to an assembly without wiring it to the Luminaire object works the same as if you grouped the objects with the Group command. The real benefit of an assembly comes from wiring the light parameters.

All other commands in the Assembly submenu work just like their counterparts in the Group menu.

Wiring Luminaire helper objects to light objects

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 parameters of the light object included in the assembly.

CROSS-REF 

You can learn more about wiring parameters in Chapter 29, "Understanding Animation and Keyframe Basics."

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. Figure 10.3 shows the Parameter Wiring dialog box for this simple assembly.

Figure 10.3: The Parameter Wiring dialog box can make the light object's Multiple parameter into a Dimmer switch.

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.

Tutorial: Creating a flashlight assembly

One of the most portable of lights is the ubiquitous flashlight. In this tutorial, we create an assembly and wire the light parameters to the Luminaire head object's parameters.

To create a flashlight assembly, follow these steps:

1. Open the  Flashlight assembly.max file from the Chap 10 directory on the DVD. This file includes a flashlight model with a single free spotlight.

2. Select all objects within the scene with the Edit Select All (Ctrl+A) menu command. Then select the Group Assembly Assemble menu command. In the Create Assembly dialog box, name the assembly Flashlight and click OK.

3. To wire the Luminaire head object's parameters to the light object, select Animation Wire Parameters Parameter Wire Dialog (Alt+5). This opens the Parameter Wiring dialog box with the Object (Luminaire) track selected in the left pane. Expand the Object (Luminaire) track, and select the Dimmer parameter.

4. In the right pane of the Parameter Wiring dialog box, expand the Flashlight track, locate and expand the Fspot01 light object, and select the Multiplier track under the Object (Free Spot) track. Then click the Control Direction arrow in the center of the dialog box that points to the right, and click Connect.

5. With the Parameter Wiring dialog box still open, select the FilterColor track in the left pane and the Color track in the right pane, and connect these two parameters with the Connect button. Click on the Close button in the upper-right corner of the dialog box.

6. In the Luminaire Parameters rollout of the Modify panel, drag the Dimmer parameter down to 1.0 and watch light in the flashlight dim.

Figure 10.4 shows the resulting flashlight assembly. This light fixture can now be positioned and used in the scene.

Figure 10.4: This flashlight assembly can be controlled using the simple Luminaire parameters.