Working with Linked Objects


If you link some objects together and set some animation keys, and the magical Play button starts sending objects hurtling off into space, chances are good that you have a linked object that you didn't know about. Understanding object hierarchies and being able to transform those hierarchies are the keys to efficient animation sequences.

All transformations are done about an object's pivot point. You can move and reorient these pivot points as needed by clicking the Pivot button under the Hierarchy panel.

Several additional settings for controlling links are available under the Hierarchy panel of the Command Panel (the Hierarchy panel tab looks like a mini-organizational chart). Just click the Link Info button. This button opens two rollouts if a linked object is selected. You can use the Locks and Inherit rollouts to limit an object's transformations and specify the transformations that it inherits.

CROSS-REF 

I present more information on object transformations in Chapter 8, "Transforming Objects-Translate, Rotate, and Scale."

Selecting hierarchies

You need to select a hierarchy before you can transform it, and you have several ways to do so. The easiest method is to simply double-click an object. Double-clicking the root object selects the entire hierarchy, and double-clicking an object within the hierarchy selects it and all of its children.

After you select an object in a hierarchy, pressing the Page Up or Page Down keyboard shortcut selects its parent or child objects. For example, if you select the Mommy duck object and press Page Down, the first baby duck object is selected and the Mommy duck object is deselected. Selecting any of the baby duck objects and pressing Page Up selects the duck object in front of it.

Linking to dummies

Dummy objects are useful as root objects for controlling the motion of hierarchies. By linking the parent object of a hierarchy to a dummy object, you can control all the objects by moving the dummy.

To create a dummy object, select Create image from book Helpers image from book Dummy, or open the Create panel, click the Helpers category button (this button looks like a small tape measure), and select the Standard category. Within the Object Type rollout is the Dummy button; click it, and then click in the viewport where you want the dummy object to be positioned. Dummy objects look like wireframe box objects in the viewports, but dummy objects are not rendered.

Tutorial: Circling the globe

When you work with complex models with lots of parts, you can control the object more easily if you link it to a Dummy object and then animate the dummy object instead of the entire model. To practice doing this, we create a simple animation of an airplane flying around the globe. To perform this feat, we create a dummy object in the center of a sphere, link the airplane model to it, and rotate the dummy object. This tutorial involves transforming and animating objects, which are covered in other chapters.

CROSS-REF 

Rotating objects is covered in Chapter 8, "Transforming Objects-Translate, Rotate, and Scale," and the basics of animation are covered in Chapter 29, "Understanding Animation and Keyframe Basics."

To link and rotate objects using a dummy object, follow these steps:

  1. Open the image from book Circling the globe.max file found in the Chap 10 directory on the DVD.

    This file includes a transparent wireframe sphere with an airplane model positioned above it. The airplane model was created by Viewpoint Datalabs.

  2. Select Create image from book Helpers image from book Dummy, and then drag in the center of the Sphere to create a Dummy object.

  3. Because the dummy object is inside the sphere, creating the link between the airplane and the dummy object can be difficult. To simplify this process, select and right-click the sphere object, and then select Hide Selection from the pop-up menu.

    This hides the sphere so that you can create a link between the airplane and the dummy object.

  4. Click the Select and Link button on the main toolbar, and drag a line from the airplane to the dummy object.

  5. Click the Auto Key button (or press N) to enable animation key mode, and drag the Time Slider to frame 100. Then click the Select and Rotate button on the main toolbar (or press E), and select the dummy object. Then rotate the dummy object about its X-axis, and notice how the linked airplane also rotates over the surface of the sphere.

  6. Select the dummy object, and right-click to access the pop-up quadmenu. Then select the Unhide All menu command to make the sphere visible again.

By linking the airplane to a dummy object, you don't have to worry about moving the airplane's pivot point to get the correct motion. Figure 10.7 shows a frame from the final scene.

image from book
Figure 10.7: With a link to a dummy object, making the airplane circle the globe is easy.




3ds Max 9 Bible
3ds Max 9 Bible
ISBN: 0470100893
EAN: 2147483647
Year: 2007
Pages: 383

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