The Channel Box - Autodesk Maya

The term channel is, for the most part, interchangeable with attribute. You can think of a channel as a container that holds the attribute’s value. The Channel Box is an editor that lists a node’s attributes for quick access. The Channel Box displays the node’s attributes, which are most frequently keyframed for animation. The Channel Box is located on the right side of the screen at the end of the status bar when the view mode button in the upper right of the status line is set to Show The Channel Box/Layer .Editor (see Figure 1.14).

 

Figure 1.14
The icon in the upper right of the interface toggles the visibility of the Channel Box.

There are two tabs on the very right side of the screen that allow you to quickly switch between the Channel Box and the Attribute Editor, as shown in Figure 1.15. (The Attribute Editor is discussed in detail later in this chapter.) These tabs are visible when both the Attribute Editor icon and the Channel Box icon are activated on the status bar in the upper-right corner of the interface.

Figure 1.15
The two tabs on the right of the screen allow you to quickly switch between the Channel Box and the Attribute Editor.

This short exercise gives a quick tour of how to work in the Channel Box:

• 1.  Create a new scene in Maya, and create a NURBS Sphere on the grid (Create > NURBS Primitives > Sphere). You’ll be prompted to draw the sphere on the grid if Interactive Creation mode is on; if not, the sphere will appear at the center of the grid. Either option is fne.

• 2.  Make sure the Channel Box is visible on the right side of the screen. To do this, click the icon at the farthest right of the status bar (shown in Figure 1.14). This is a toggle to display the Channel Box. Click it until the Channel Box appears, as in Figure 1.16.

• 3.  The Channel Box will list the currently selected object. Select the sphere, and you’ll see nurbsSphere1 appear. The list below it shows the attributes for the nurbsSphere1’s transform node. The lower half of the Channel Box lists the connections to this node. You’ll see the name of the associated shape node under SHAPES, and below this a section for the inputs. In this case, the input is the history node, named makeNurbSphere1, which contains the original settings used to create the sphere. If you delete history on the sphere, these attributes will no longer be accessible.

 Figure 1.16
The Channel Box displays the channels for the currently selected object.

• 4.  In the upper section of the Channel Box, under nurbsSphere1, try selecting the felds and inputting different values for Translate, Scale, and Rotate. The sphere updates its position, orientation, and size.

• 5.  In the Visibility channel, select the word On in the feld, and type 0. The sphere disappears. Input the value 1, and it reappears. Visibility is a Boolean, meaning it is either on or off, 1 or 0.

• 6.  Select the Translate X feld so it is highlighted. Shift+click the Rotate Z value, and all the values in between are also selected. 

• 7.  Type 0 in the Translate X feld while they are selected, which sets all the Translate and Rotate values to the same value, places the sphere at the center of the grid, and returns it to its original orientation (see Figure 1.17).

Figure 1.17
You can quickly “zero out” the Translate and Rotate channels by Shift+clicking their felds and entering 0

 

• 8.  In the makeNurbsSphere section, highlight the Start Sweep channel. Enter a value of 90, and the sphere opens up. You’re altering the construction history of the sphere so it is no longer a closed surface.

• 9.  Select the word Sections so it is highlighted in blue. MMB-drag in the viewport view back and forth. Doing this creates a virtual slider so you can change the value of the feld interactively instead of numerically. This should work for all the channels (most of the time).

• 10.  Set the timeline to frame 1, and press the s hot key. You’ll see all the channels turn orange, indicating that they have been keyframed. The s hot key keyframes all the available channels. 

• 11.  Move the timeline to frame 24, and change some settings on both the transform node (the upper half of the Channel Box) and under makeNurbsSphere1. 

• 12.  Press the s hot key again to set another key. Play the animation, and you’ll see the sphere update based on the keyframed changes. The s hot key keyframes everything, even those channels you may not need to keyframe. You can use the Channel Box to keyframe specifc channels.

• 13.  Rewind the timeline, and choose Edit > Keys > Delete Keys to remove all the keyframes on the sphere.

• 14.  Highlight Translate X and Shift+click Translate Z so that the translation channels are all selected. 

• 15.  Right-click these values, and choose Key Selected (see Figure 1.18).

 

Figure 1.18
Right-click the selected channels, and choose Key Selected to animate just those specifc channels.

• 16.  Move to frame 24, and enter different values in the Translate felds. 

• 17.  Right-click and choose Key Selected. This places a keyframe on just the selected channels, which is often a cleaner and more effcient way to work because you’re placing keyframes only on the channels you need to animate and not on every keyable channel, which is what happens when you use the s hot key.

Be thrifty with Keyframes
Creating extra, unnecessary keys leads to a lot of problems, especially when you start to refne the animation on the Graph Editor (discussed in Chapter 5). Keyframes also can increase the scene size (the amount of storage space the scene uses on disk). Be cheap with your keyframes, and use the Key Selected feature to keyframe only the channels you need. Avoid using the s hot key to create keys on everything.

• 18.  To remove keys, you can highlight the channels, right-click, and choose Break Connections. This removes any inputs to those channels. The values for the current keyframe will remain in the channels.

1. The channels are color coded to show what kind of input drives the channel:
   Pink indicates a keyframe.    
2. Purple indicates an expression.     
3. Yellow indicates a connection (as in a connection from another node or channel made in   the Connection Editor).
4. Brown indicates a muted channel.   
   Gray means the channel is locked.

Locking and Muting Channels
You can mute a channel by right-clicking it and choosing Mute Selected from the pop-up menu. When you mute a channel, the keyframes on that channel are temporarily disabled; as long as the channel is muted, the animation will not update. This is useful when you want to disable the keyframes in a channel so that you can focus on other aspects of the animation. Locking a channel is another option available when you right-click selected channels in the Channel Box. A locked channel prevents you from adding keyframes to a channel regardless of whether it has been animated. Animation techniques are explored further in Chapter 5.

The Channel Box will be explored throughout the book and used frequently, particularly in the chapters concerning animation.

 

 

next The Attribute Editor  - Maya Autodesk

By Eric Keller with Todd Palamar and Anthony Honn

Copyright © 2010 by Wiley Publishing, Inc., Indianapolis, Indiana