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Mastering 3D Studio MAX R3

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Space Warps

After the master object, modifiers, and transforms have been evaluated, MAX evaluates all of the space warps that have been applied to the object. Like modifiers, space warps deform object geometry. The difference is that the effect of a space warp upon an object changes as the object is transformed in space. Space warp bindings—the short tags that indicate that a space warp had been applied to an object—appear at the top of the modifier stack, above the master object and its modifiers and transforms (see Figure 2.11).


FIGURE 2.11  Space warp bindings are separated from an object’s modifiers by a double line.

Object Properties

MAX evaluates object properties last. Object properties include the name, color, material assignment, display properties, linking information, G-buffer ID number, and attributes of rendering such as shadow casting and receiving. These properties can be viewed by right-clicking a selected object and opening the Object Properties dialog box (displayed in Figure 2.12).

Of all the object properties, materials provide the biggest opportunity for variation. Some materials cover the surface of an object like wallpaper; others go through to the core. They give objects characteristics like color, pattern, texture, shininess, and transparency. These effects can be layered or combined with maps to simulate the complexity of real-world surfaces (as shown in Figure 2.13).

You add maps to materials by linking the program to external image files or by generating maps from internal procedures. Both image maps and procedural maps may be animated. After you have incorporated a map into a material (like the box in Figure 2.14), you can manipulate its color attributes and its surface projection coordinates.


FIGURE 2.12  The Object Properties dialog box allows you to change existing properties and define your own.


FIGURE 2.13  The material on this teapot uses a Cellular procedural map for its Diffuse map as well as its Opacity map.


FIGURE 2.14  Mirroring and tiling commands cause a map to repeat across the surface of the box. (The original map was Cloud2.jpg, which ships with MAX.)

Unlike image maps, which are limited to a two-dimensional array of pixels even when wrapped around a 3D object, procedural maps can be three-dimensional: the map itself has depth. This means that when you cut away a part of an object with Boolean subtraction, the map pattern continues on the inside surfaces. Procedural maps (like the one in Figure 2.15) are generated by the program in a mathematical “procedure.”


FIGURE 2.15  A 3D procedural map is revealed inside the cutaway surface of the sphere. Notice its continuity with the outside surface.

Materials can incorporate an unlimited number of maps. To keep track of them, MAX places the maps in a branching hierarchy called a material tree. This hierarchy can be viewed with the Material/Map Navigator and the Material/Map Browser (see Figure 2.16).


FIGURE 2.16  A complex material and its hierarchy displayed in the Material/Map Navigator

Understanding MAX’s Concepts of Space

In Chapter 1, you learned how 3D space begins at a defined origin and extends infinitely into space, using the X, Y, and Z axes to measure distance. Now, let’s look at how different systems of reference can be used to measure space from different perspectives.

A system of reference is a navigational tool that indicates your position and orientation. You select different systems of reference from the Reference Coordinate System drop-down list (on the Main Toolbar) depending on where you are and what you are doing.The most important systems of reference are the world coordinate system and the local coordinate system. World coordinates define the space of the entire scene, or world space; local coordinates define the space around an object, or object space. The other coordinate systems are variations on world or local systems of reference that are used for performing object transforms under specific circumstances.

World Coordinates

The world coordinate system measures space in absolute terms using a fixed system of reference. You can think of it as an intergalactic system of navigation, with the origin of the universe at its core. The program uses this system to keep track of all of the objects in your scene. Use this system to locate objects in relation to the entire scene.

Whenever you select an object, MAX displays X, Y, and Z axes that reflect the current coordinate system. World coordinates are fixed in space; the axes shown match those of the home grid, as in Figure 2.17, no matter which way the object is pointed.


FIGURE 2.17  Using world coordinates, the axes of the object’s home grid always align to the axes of the world coordinate system.

Local Coordinates

The local coordinate system is an object-based system that uses the pivot of an object as its origin (as illustrated in Figure 2.18). If world coordinates measure the universe, then local coordinates measure planetary space. The position and orientation of an object’s local coordinate system is measured and indicated by the object’s pivot. This is the system that the program uses when it modifies the geometry of an object, or performs a transform in local coordinates.


FIGURE 2.18  The axes of the local coordinate system indicate the position and orientation of an object.

Screen Coordinates

Screen coordinates align the axes to the view plane of the monitor screen. X and Y align horizontally and vertically to the screen, with Z directed in and out of the screen (as in Figure 2.19). This orientation persists no matter how you rotate your view of the scene. Use screen coordinates whenever you want to transform an object in relation to the edges of an active viewport.


FIGURE 2.19  Screen coordinates always “face” the viewer.

View Coordinates

View coordinates align to the visible plane of the home grid (see a top view example in Figure 2.20). In a variation on world coordinates, in view coordinates, the Z axis always points away from the grid. View coordinates are thus not a fixed system of reference, because different grid planes face different ways in different views.


FIGURE 2.20  In view coordinates, the Z axis always points away from the grid.

Grid Coordinates

Grid coordinates align to the visible plane of the active grid (see Figure 2.21). At first glance, grid coordinates seem identical to view coordinates, in that the Z axis is placed perpendicular to the visible grid. The difference is that grid coordinates align not just to the home grid, but to any grid that is active, including user grids. Use this system when you want to transform objects with respect to the planes and axes defined by a grid object.


FIGURE 2.21  Grid coordinates align to the visible plane of the active grid.

Parent Coordinates

Parent coordinates align to the local coordinates of an object’s parent (see Figure 2.22). When the parent coordinate system is chosen, child objects transform with respect to the local coordinate system of their parent objects. This is different than linking, in which the child inherits the transforms of a parent using whatever transform coordinate system is selected. If an object is not linked to a parent, it is considered a child of the world, and uses the world coordinate system by default. This system is useful when developing inverse kinematics.

Pick Coordinates

Pick coordinates align to the local coordinates of any object that you choose (see Figure 2.23). Like the parent coordinate system, pick coordinates use the local coordinates of another object as the locus of transforms. The difference is that pick coordinates allow you to select any other object in the scene as the locus of transformation. Use this system when you want to transform one object in relation to another without linking them in other ways.


FIGURE 2.22  Parent coordinates align to the local coordinates of an object’s parent.


FIGURE 2.23  Pick coordinates align to the local coordinates of any object you choose.

Understanding MAX’s Concepts of Time

In animation, time is a series of discrete moments strung together by the eye and mind. When you view a rapid succession of images, each one persists in your memory long enough to superimpose it on the one that follows. When the images depict a logical progression across a sequence of frames, your mind interprets the images as animation.


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