In Maya's original design, the approach taken was called the dependency graph. The idea is that everything in the sceneevery curve, object, link, image, texture, keyframe, and so forthand every tweak made to those items would be considered one "thing." Actually, not "thing"; the name they use is node, but it means about the same. It's one building block of the scene. These building blocks link to create ever more complex things. For example, when a profile line is drawn in Maya, it becomes a node. When the line is revolved to create, for example, a vase, the underlying line is still there. Further, the revolve operation creates a "revolve" node, placed in history, thus letting you modify the original curve and the revolve parameters independently.
Modifications made to the line immediately affect the vase's shape, and the modifications themselves create a node so that you can undo or modify anything you've done before. This flexibility underlies the entire Maya product, and includes the option to disable or delete history, which animators often use for efficiency.
The dependency graph architecture is simple to understand and allows tremendous flexibility. Maya allows the animator to view a scene file with every dependency revealed by using a view called the Hypergraph. There, links can be broken and reconnected so that any variable can control virtually any other variable. This feature illustrates one reason for Maya's popularity with Hollywood: A technician can set up dependencies so that the animator's work is minimized. When a character tilts her head back, the skin stretches, the muscles appear to move and bulgeand this all happens automatically because it has been set up to work that way in Maya. Naturally, setting up complex dependencies takes time, but the investment is easily justifiable for a character that will be used often. Programming skills are rarely required, however. It's simply a matter of learning what's possible and becoming proficient in setting up these dependencies. As Maya becomes more popular with animators of all types, this type of "TD work" (named for the technical directors of projects that typically perform this work) is becoming something everyone does, so long as it saves time and effort overall.
Most of the time when you animate with Maya, your right hand controls the three-button mouse, and your left hand is at the left side of the keyboard. This puts your left hand in position to operate the primary hotkeys, the spacebar, the Alt and Ctrl keys, and other keyboard shortcuts that get heavy use. Left-handed users who keep the mouse at the left of their keyboard need to reprogram the default hotkeys that put all the primary keys at the keyboard's left side.
Using the Three Mouse Buttons
Maya uses all three buttons of the mouse constantly. The left mouse button (LMB) is used to select and pick things, and often it's used to take actions such as moving or rotating an object. The right mouse button (RMB) usually brings up a selection list (which you might be familiar with in other programs as a pop-up menu or a context-sensitive menu) for you to pick from with the LMB. The middle mouse button (MMB) is used for adjusting interim thingsfor example, dragging and dropping materials to the scene or moving part of an object with snapping temporarily engaged.
Using the Spacebar
The spacebar has two functions. The first is the full-screen window toggle, where a brief tap of the spacebar causes a window to toggle to full screen. The window that switches to full screen is always the one that the mouse cursor is currently hovering over. When a fresh install of Maya starts, it's in the typical Four View mode, with Top, Side, Front, and Perspective views; however, the Perspective view is maximized. If you briefly tap the spacebar, the four screens appear. You can then maximize any of the other views.
The other function of the spacebar is to open the Hotbox by holding down the spacebar. The Hotbox is described in detail near the end of this chapter.
Manipulating a View
As you build and manipulate objects, you need to be able to quickly adjust your viewpoint interactively. A primary part of knowing Maya is its window manipulation method. You can position yourself anywhere in a scene by using tumble, track, and dolly controls.
With the tumble control, also known as orbit or spin, you move your orbital position in relation to the scene. Hold down the Alt key with your left hand while you click and drag with the LMB in a perspective viewport.
With the track control, also known as pan or move, you laterally move your view of the screen. That is, without changing angle or zoom level, the viewpoint moves up, down, left, or right. Hold down the Alt key with your left hand while you click and drag with the MMB in any viewport.
You cannot tumble an orthogonal view because Side, Top, and Front views by default do not rotate (orthogonal camera settings are discussed in Chapter 11, "Cameras and Rendering"). These views are locked in place. The term orthogonal means the views have no perspective or vanishing point.
With the dolly control, also known as zoom, you can interactively zoom in and out of a scene. Hold down the Alt key with your left hand while you click and drag with both the LMB and MMB pressed. You can also zoom into or out of a drawn rectangle by using these methods:
Zoom window You can click-drag a window that outlines an area you want to zoom into, a technique that CAD users are particularly fond of. To zoom into a window, hold down the Ctrl and Alt keys with your left hand while you drag a window with the mouse holding down the LMB. Drag the rectangle from the upper-left corner to the lower-right corner.
Zoom out window If you perform the same steps for a zoom window but drag the rectangle from the lower-right corner to the upper-left corner, the window is zoomed back. The smaller the window, the greater the zoom outward.
All these tools except the tumble work throughout Maya. That is, every graphical Maya dialog box that appears, from Render windows to Hypershade and even the Paint Effects palette, can be tracked and dollied and zoom-windowed. You will use these tools constantly to focus your work area and also to avoid eye strain. Don't forget this when a dialog box appears with text so tiny that it's unreadable!
Saving a View
Every panel has its own Bookmark Editor so that you can save your views. This can be a big timesaver when you have perfectly aligned some objects in a panel and then need to adjust the panel to edit something else. To add a bookmark for a panel, open the Bookmark Editor with View | Bookmarks | Edit Bookmarks. You can type in the bookmark name and even include a description. Now the bookmark will appear above the Edit Bookmarks item under View | Bookmarks in that panel.
Each panel has its own bookmarks, exclusive of the others. If you can't find a bookmark you made, you are probably looking in the wrong panel or originally made the bookmark in the wrong panel.