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

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Displaying Options in the Outliner

There are several options in the Outliner for displaying nodes and their hierarchical arrangements. You can see that the default perspective, top, side, and front cameras are visible as nodes at the top of the Outliner. Also, there are a number of sets such as the defaultLightSet that appear at the bottom of the Outliner. These sets are mainly used for organization of data by Maya and are usually not directly edited or altered.

• 1.  In the Display menu of the Outliner, select the Shapes option to display the shape nodes of the objects. The shape nodes appear parented to their respective transform node. You can select either the transform node or the shape node in the Outliner to select the object.

accessing Outliner Options
You can right-click in the Outliner to quickly access the Outliner’s display options rather than use the menu at the top of the Outliner.

• 2.  In the Display menu, activate the visibility of attributes by selecting the Attributes (Channels) option. Each node now has an expandable list of attributes. Most of the time you may want this option off because it clutters the Outliner and there are other ways to get to these attributes. Ultimately, how you use these options is up to you.

• 3.  Turn off the Attributes display, and turn off the DAG Objects Only option. This allows you to see all the nodes in the scene in the Outliner list as opposed to just the DAG nodes.

DAG stands for “Directed Acyclic Graph,” and DAG objects are those objects that have both a shape and a transform node. It’s not really crucial to understand exactly what Directed Acyclic Graph means as long as you understand that it is an arrangement in which a shape node is parented to a transform node. When you turn off DAG Objects Only in the Outliner, you’ll see all the nodes in the Maya scene appear. Many of these are default utility nodes required to make Maya function, such as the renderLayerManager node or the dynController1 node. 

Many other nodes appear when you create a new node or connection. An example of this would be a keyframe or an expression node.When you turn off DAG Objects Only, the list can get quite long. To fnd a node quickly, you can type the node’s name in the feld at the very top of the Outliner. This hides all nodes except the named node. Clearing the feld restores the visibility of all nodes in the Outliner (see
Figure 1.13).

 

Figure 1.13
The Outliner can display shape nodes as well as other types of nodes in the scene.

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Creating Node Hierarchies in the Outliner

The Outliner shows a hierarchical list of the nodes in the scene in a form similar to the outline of a book. It is another way to view the transform and shape nodes in a scene and a way to create hierarchical relationships between nodes through parenting. The Outliner does not show the connections between nodes like the Hypergraph; rather, it shows the hierarchy of the nodes in the scene. To see how this works, try the following exercise:

• 1.  Open the miniGun_v01.ma fle from the Chapter1/scenes directory on the DVD. The scene consists of a minigun model in three parts.

• 2.  Open the Outliner by choosing Window > Outliner.

Outliner Layout presets
The Outliner can be opened as a separate panel or, like many of the panels in Maya, can be opened in a viewport. A popular window arrangement is to split the viewports into two views, with the left view set to the Outliner and the right view set to the perspective view. You can open this arrange-ment by going to the menu bar in a viewport window and choosing Panels > Saved Layouts > Persp/Outliner (as shown here). You can also click the third layout button on the left side of the interface just below the toolbox.

• 3.  At the top of the Outliner is a menu bar. In the Display menu, make sure DAG Objects only is selected and Shapes is deselected (see Figure 1.10). In the Outliner, you’ll see three nodes listed: gunBarrels, housing, and mount in addition to the four default cameras and several set nodes (don’t worry about the set nodes). These are the three transform nodes for the pieces of the minigun. Select each node, and you’ll see the corresponding part highlighted in the perspective view. At the moment, each piece is completely separate and unconnected.

Figure 1.10
The Display menu at the top of the Outliner

• 4.  Select the housing node, and switch to the Rotate tool (hot key = e). 

• 5.  Rotate the objects; nothing else is affected. Try moving housing (hot key = w); again,
  nothing else is affected.

• 6.  Hit Undo a few times until the housing node returns to its original location and
  orientation.

• 7.  In the Outliner, select the gunBarrels object. Then Ctrl+click the housing object, and choose Edit > Parent.Parenting one object to another means you have made one transform node the child of the second. When an object is a child node, it inherits its position, rotation, scale, and visibility from the parent node. In the Outliner, you’ll notice that the housing node has a plus sign beside it and the gunBarrels node is not visible. The plus sign indicates that the node has a child node.

• 8.  Click the plus sign next to the housing node to expand this two-node hierarchy. The  gunBarrels node is now visible as the child of the housing node. 

• 9.  Select the housing node, and try rotating and translating it. The gunBarrels node follows the rotation and translation of the housing node (see Figure 1.11).Unlike the situation presented in the “Connecting Nodes with the Connection Editor” section of the chapter, the rotation and translation of the gunBarrels object are not locked to the rotation and translation of the housing node; rather, as a child, its rotation, translation, scale, and visibility are all relative to that of its parent.

 Figure 1.11
When the gunBarrels node is made a child of the housing object, it inherits changes made to the housing object’s transform node.

• 10.  Select the gunBarrels node, and try rotating and translating the object; then rotate and translate the housing node. You’ll see the gun barrels maintain their position relative to the housing node. You could create an animation in which the gun barrels rotate on their own z-axis to spin around while fring, while the housing node is animated, rotating on all three axes in order to aim.

• 11.  Hit Undo a few times (hot key = Ctrl+z) until both the housing and gunBarrel objects are back to their original positions. 

• 12.  In the Outliner, select the housing node, and MMB-drag it on top of the mount node. This is a way to quickly parent objects in the Outliner.

• 13.  Click the plus signs next to the mount and housing nodes in the Outliner to expand the hierarchy. The lines indicate the organization of the hierarchy; the gun barrels are parented to the housing node, which is parented to the mount node

Shift+click to expand the hierarchy
You can expand an entire hierarchy with one click in the Outliner. Just Shift+click the arrow for the hierarchy you want to expand.

• 14.  Select the mount node, and choose Edit > Duplicate (hot key = Ctrl+d). This makes a copy of the entire hierarchy. The duplicated mount node is named mount1. 15.  Select the mount1 node, and switch to the Move tool (hot key = w). Pull on the red  arrow of the tool to move the duplicate along the x-axis about two units.

• 16.  Select the mount node, and then Ctrl+click the mount1 node in the Outliner. 

• 17.  Choose Edit > Group (hot key = Ctrl+g) to group these two nodes under a single  parent node.A group node is a transform node that has no shape node. It’s just a location in space used to organize a hierarchy. Like a parent node, its children inherit its rotation, translation, scale, and visibility.

• 18.  Select the group1 node, and Shift+click the plus sign next to it in the Outliner to expand the group and all its children. 
• 19.  Double-click the label for the group1 node in the Outliner to rename it; rename the 
  group guns.

Renaming Nodes
You’ll notice that the duplicate mount node has been renamed mount1 automatically. Nodes on the same level of the hierarchy can’t have the same name. The child nodes do have the same name, and this is usually a bad idea. It can confuse Maya when more complex connections are made between nodes. Whenever youencounter this situation, you should take the time to rename the child nodes so that everything in the scene has a unique name.

• 20.  Select the mount1 node in the Guns hierarchy, and choose Modify > Prefx Hierarchy Names. 

• 21.  In the pop-up window, type right_. This renames the top node and all its children so that “right_” precedes the name. Do the same with the other mount node, but change the prefx to left_.

• 22.  Select the guns group, and choose Modify > Center Pivot. This places the pivot at the center of the group. Try rotating the Guns group, and you’ll see both guns rotate together (see Figure 1.12).

Figure 1.12
The Guns group is rotated as a single unit.

Each member of the hierarchy can have its own animation, so both gun barrels can rotate around their z-axes as they fre, the two housing nodes could be animated to aim in different directions, and the two guns could rotate as one unit, all at the same time. The entire group can be parented to another node that is part of a vehicle.

 

next Creating Node Hierarchies in the Outliner

 

 

By Eric Keller with Todd Palamar and Anthony Honn

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

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Connecting Nodes with the Connection Editor

Connections between nodes can be added, deleted, or changed using the Hypergraph and  the Connection Editor.

1. Start a new Maya scene. 
2. Create a locator in the scene by choosing Create > Locator. A simple cross appears at the center of the grid in the viewport. This locator is a simple nonrendering null that indicates a point in space. Locators are handy tools that can be used for a wide variety  of things in Maya.
3. Press the w hot key to switch to the Move tool; select the locator at the center of the grid, and move it out of the way.
4. Press the g hot key to create another locator. The g hot key repeats the last action you performed, in this case the creation of the locator.
5. Create a NURBS sphere in the viewport by choosing Create > NURBS Primitives > Sphere. If you have Interactive Creation selected, you’ll be prompted to drag on the grid in the viewport to create the sphere; otherwise, the sphere will be created at the center of the grid based on its default settings.

NURBS
A Non-Uniform Rational B-Spline (NURBS) object is a type of surface that is defned by a network of editable curves. Chapter 3 introduces how to create and model NURBS surfaces

    6.  Move the sphere away from the center of the grid so you can clearly see both locators and the sphere.

    7.  Use the Select tool (hot key = q) to drag a selection marquee around all three objects.

    8.  Open the Hypergraph in connections mode by choosing Window >Hypergraph:Connections. You 

         should see eight nodes in the Hypergraph (see Figure 1.6). 

 

Figure 1.6
The input and output connections of the two locators and the sphere are graphed in the Hypergraph.

          locator1 and locator2 are the two transform nodes for the locators. locatorShape1 and locatorShape2 

          are the two shape nodes for the locators. nurbsSphere1 is the transform node for the NURBS sphere. 

          And nurbsSphereShape1 is the shape node for the sphere; it’s connected to MakeNurbsSphere1, 

         which is the history node, and to initialShadingGroup. The initialShadingGroup node is the default 

         shading group that is applied to all geometry; without this node, the geometry can’t be shaded or  

         rendered. When you apply a new shader to an object, the connection to initialShadingGroup is  

         replaced  with a connection to the new shader

      9.  In the Hypergraph window, use Alt+RMB to zoom out a little. 

     10.  Select the locator1, locator2, and nurbsSphere1 nodes, and drag them away from the other nodes 

            so   you can work on them in their own space.

     11.  In the Hypergraph, MMB-drag the locator1 node over the nurbsSphere1 node. 

     12.  From the pop-up menu, choose Other at the bottom (Figure 1.7). A new dialog box will open; this is 

            the Connection Editor

 

Figure 1.7
You can connect two nodes in the Hypergraph by MMB-dragging one on top of the other and choosing from the options in the pop-up menu.

The Connection Editor is where you create and edit connections between nodes. The  left side of the panel represents the output of a selected node, in this case the locator1 node. The output is the controlling node; the right side is the input, and in this case is nurbsSphere1, which will be controlled based on whatever connections you make in  the list.

The list represents the attributes of each node. Any of the attributes that have a plus sign next to them can be expanded to reveal nested attributes. For instance, fnd the Translate attribute in the left side of the column, and expand it by clicking the plus sign. You’ll see that Translate has Translate X, Translate Y, and Translate Z. This means you can choose either to select the Translate attribute, which will automatically use all three nested attributes as the output connection, or to expand Translate and choose one or more of the nested Translate X, Y, or Z attributes as the output connection. In some situations, a connection becomes grayed out, indicating that the connection between the two attributes cannot be made, usually because the connection is not appropriate for the selected attri-butes (see Figure 1.8).

Figure 1.8
The Connection Editor specifes which attributes are connected between nodes.

13.  Select the Translate attribute on the left. You’ll notice that many of the selections on the right side become grayed out, meaning that they cannot be connected to Translate. This is because Translate is a vector—it is an output consisting of three connections (Translate X, Translate Y, and Translate Z). The vector can be connected only to other vectors on the right side of the list.

14.  On the right side, scroll down and select Translate. Both connections in the list are itali-cized, indicating that there is a connection to this attribute. If one of the other attributes on the right were italicized, it would indicate that another node is already connected to that attribute (see Figure 1.8).

15.  In the viewport, switch to wireframe mode. You can do this by pressing 4 on the keyboard or clicking the wireframe icon on the icon bar at the top of the viewport window; the wireframe icon is the wireframe cube.

16.  In the viewport, you’ll notice that the sphere has snapped to the same position as the locator. Select the sphere, and try to move it using the Move tool (hot key = w). The sphere is locked to the locator, so it cannot be moved. Select the locator, and try to move it; the sphere moves with the locator. The output of the locator’s Translate attributes are the input for the sphere’s Translate.

Incoming Connections
In wireframe view, an object will be highlighted in purple if it has an incoming connection from
the selected object.

17.  Select the nurbsSphere1 node in the Hypergraph, and MMB-drag it on top of locator2. 

18.  From the pop-up list, choose Rotate (see Figure 1.9). The Connection Editor opens again.

Figure 1.9
The nurbsSphere1 node is MMB-dragged on top of the locator2 node, making the sphere the input connection for locator2.

Specifying Connections
In some cases when you choose to make a connection from the pop-up window, Maya will automati-cally make it for you without opening the Connection Editor; however, in other cases, even when you choose what seems like an obvious connection from the list, Maya will still open the Connection Editor so you can make exactly the connection you want.

19.  Now the nurbsSphere1 node is listed on the left, and locator2 is on the right. Find the Rotate attributes, expand the list, and choose Rotate X from the list.

20.  On the right side, fnd the Rotate attributes, expand them, and choose Rotate Y. This causes the Rotate X of the nurbsSphere1 node to control the Rotate Y of the locator.

21.  In the viewport, select the sphere, and switch to the Rotate tool (hot key = e). 

22.  Drag up and down on the red circle of the tool to rotate the sphere in X only. The locator
rotates around its y-axis.

Use the Connection editor to Make Simple Connections
The Connection Editor is best used when you want to make a one-to-one relationship between attributes on two nodes. In other words, the value of the output connection needs to equal exactly the value of the input connection. More complex connections can be made using expressions, special nodes, or Set Driven Key. All of these options will be discussed throughout the book.

You can break a connection by reselecting the connected node on either side of the Connection Editor so that the attribute is no longer highlighted. You can also select the connecting line in the Hypergraph and press the Delete key to break the connection.

 

next Creating Node Hierarchies in the Outliner

 

 

By Eric Keller with Todd Palamar and Anthony Honn

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

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Using the Hypergraph

The Hypergraph is a picture of the nodes and their connections in Maya. A complex scene can look like a very intricate web of these connections. When you really need to know how a network of nodes isconnected, the Hypergraph gives you the most detailed view. There are two ways to view the Hypergraph, the hierarchy view and the connections view:

• The  hierarchy view shows the relationships between nodes as a tree structure.
• The  connections view shows how the nodes are connected as a web.

You can have more than one Hypergraph window open at the same time, but you are still looking at the same scene with the same nodes and connections. This short exercise gives you a sense of how you would typically use the Hypergraph:

1. Create a new Maya scene. 
2. Create a polygon cube by choosing Create > Polygon Primitive s> Cube. 
3. You will be prompted to draw a polygon on the grid by dragging on the surface. Drag a square on the grid, release the cursor, and then drag upward on the square to turn it into a three-dimensional cube (see Figure 1.2). Release the mouse button to complete the cube. At this point, feel free to make your own decisions about the size and position of the cube on the grid.
4. Select the cube in the viewport, and choose Window > Hypergraph > Hierarchy to open the Hypergraph in hierarchy mode. You’ll see a yellow rectangle on a black feld labeled pCube1. The rectangle turns gray when deselected.

Figure 1.2
When Interactive Creation is on, Maya prompts you to draw the object on the grid in the scene.

Interactive Creation
By default Maya creates objects using the Interactive Creation method, which allows you to draw on the canvas as you create your geometry. To turn this feature off, choose the Create > Polygon Primitives menu, and deselect the Interactive Creation option at the bottom of the menu. While the Interactive Creation mode is on, you can deselect the Exit On Completion method; this means that each time you draw on the grid, you will continue to create cubes until you switch to another tool.

5.  Hold the right mouse button down, and hover the cursor over the pCube rectangle. Choose Rename from 

     the pop-up window. Rename the cube myCube.

6.  Select myCube, and choose, from the Hypergraph menu, Graph > Input And Output connections. This 

     switches the view to the connections view just as if you had originally opened the Hypergraph by choosing 

    Windows >  Hypergraph:Connections. It’s the same Hypergraph, but the view mode has changed, 

    allowing you to see more of the scene.

Navigating the hypergraph
You can navigate the Hypergraph by using the same hot key combination you use in the viewport: Alt+MMB-drag pans through the Hypergraph workspace, and Alt+RMB-drag zooms in and out. Selecting a node and pressing the f hot key focuses the view on the currently selected node. (MMB means clicking with the middle mouse button, and RMB means clicking with the right mouse button.)

When you graph the input and output connections, you see the connected nodes that make up an object and how the object appears in the scene. In the current view, you should see the myCube node next to a stack of connected nodes labeled polyCube1, myCubeShape, and initial-ShadingGroup, as shown in Figure 1.3. (The nodes may also be arranged in a line; the actual position of the nodes in the Hypergraph does not affect the nodes themselves.)

Figure 1.3
The node net-work appears in the Hypergraph. This shape node (myCubeShape) is connected to two other nodes, while the transform node (myCube) appears off to the side.

The myCube node is the transform node. The myCubeShape node is the shape node. In the Hypergraph, the shape and transform nodes are depicted as unconnected; however, there is an implied connection, as you’ll see later. This is demonstrated when you rename the myCube node; the shape node is renamed as well. In Maya, the construction history feature stores a record of the changes used to create a particular node. The polyCube1 node is the construction history node for the myCubeShape node. 

When you frst create a piece of geometry, you can set options to the number of subdivisions, spans, width, height, depth, and many other features that are stored as a record in this history node. Additional history nodes are added as you make changes to the node. You can go back and change these settings as long as the history node still exists. Deleting a history node makes all the previous changes to the node permanent (however, deleting history is undoable).

1. Keep the Hypergraph open, but select the cube in the viewport. 
2. Set the current menu to Polygons (you can change the menu set by choosing Polygons from the menu in the upper left of the Maya interface).
3. Choose Mesh > Smooth. The cube will be subdivided and smoothed in the viewport. In the Hypergraph you’ll see a new polySmoothFace1 node between the polyCube1 node and the myCubeShape node (see Figure 1.4). This new node is part of the history of the cube.
4. Select the polySmoothFace1 node, and delete it by pressing the Backspace key on the key-
   board. The cube will return to its unsmoothed state

Figure 1.4
Performing a smooth operation on the cube when construction history is activated causes a new polySmoothFace node to be inserted into the node  network.

Working with history
Over the course of a modeling session, the history for any given object can become quite long and complex. This can slow down performance. It’s a good idea to periodically delete history on an object by selecting the object and choosing Edit > Delete By Type > History. You can also choose to delete all the history in the scene by choosing Edit > Delete All By Type > History. Once you start animating a scene using deformers and joints, you should not delete the history or use the Delete By Type > Non-Deformer History option.

       5.  Select the transform node (myCube), and press the s hot key. This creates a keyframe on all the 

            channels of the transform node. You’ll see a new node icon appear for each keyframed channel with 

            a connection to the transform node (see Figure 1.5).

       6.  Hold the cursor over any line that connects one node to another. A label appears describing the 

            output and input attributes indicated by the connection line

Figure 1.5
The attributes of myCube’s trans-form node have been keyframed. The keyframe nodes appear in the Hypergraph.

Connecting Nodes with the Connection Editor

By Eric Keller with Todd Palamar and Anthony Honn

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

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Creating and Editing Maya Nodes - Autodesk Maya

A Maya scene is a system of interconnected nodes that are packets of data about what exists within the world of a Maya scene. The nodes are the building blocks you, as the artist, put together to create the 3D scene and animation that will fnally be rendered for the world to see. So if you can think of the objects in your scene, their motion, and appearance as nodes, think of the Maya interface as the tools and controls you use to connect those nodes. 

The relationship between these nodes is organized by the Dependency Graph, which describes the hierarchical relationship between connected nodes. The interface provides many ways to view the graph, and these methods are described in this chapter.Any given workfow in Maya is much like a route on a city map. There are usually many ways to get to your destination, and some of these make more sense than others depending on where you’re going. In Maya, the best workfow depends on what you’re trying to achieve, and there is usually more than one possible ideal workfow. 

There are many types of nodes in Maya that serve any number of different functions. All the nodes in Maya are considered Dependency Graph (DG) nodes. Let’s say you have a simple cube and you subdivide it once, thus quadrupling the number of faces that make up the cube. The information concerning how the cube has been subdivided is contained within a DG node that is connected to the cube node.A special type of DG node is the Directed Acyclic Graph (DAG) node. These nodes are actually made of two specifc types of connected nodes: transform and shape. The arrangement of DAG nodes consists of a hierarchy in which the shape node is a child of the transform node.
 

Most of the objects you work with in the Maya viewport, such as surface geometry (cubes, spheres, planes, and so on), are DAG nodes.To understand the difference between the transform and shape node types, think of a transform node as describing where an object is located and a shape node as describing what an object is.The simple polygon cube in Figure 1.1 consists of six fat squares attached at the edges to form a box. Each side of the cube is subdivided twice, creating four polygons per side. That basically describes what the object is, and the description of the object would be contained in the shape node. 

This simple polygon cube may be 4.174 centimeters above the grid, rotated 35 degrees on the x-axis, and scaled four times its original size based on the cube’s local x- and y-axes and six times its original size in the cube’s local z-axis. That description would be in the transform node (see Figure 1.1).

Figure 1.1
A shape node describes the shape of an object and how it has been constructed; a transform node describes where the object is located in the scene.

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By Eric Keller with Todd Palamar and Anthony Honn

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

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