3ds Max 2012 Bible - Kelly L. Murdock [73]
The Scale Multiplier value determines how many times larger the plane should be at render time. Both Length and Width are multiplied by equal values. The Density Multiplier specifies the number of segments to produce at render time. The Total Faces value lets you know how many polygons are added to the scene using the specified Density Multiplier value.
Using these multipliers, you can create a small Plane object in the scene that automatically increases to the size and density it needs to be when rendered. This allows you to use the Zoom Extents button to see all objects without having a huge Plane object define the extents.
Extended Primitives
You access the Extended Primitives by selecting Extended Primitives in the subcategory drop-down list in the Create panel. These primitives aren't as generic as the Standard Primitives, but are equally useful, as shown in Figure 5.15.
FIGURE 5.15
The Extended Primitives: Hedra, ChamferBox, OilTank, Spindle, Gengon, RingWave, Hose, Torus Knot, ChamferCyl, Capsule, L-Ext, C-Ext, and Prism
Hedra
Hedras, or Polyhedra, form the basis for a class of geometry defined by fundamental mathematical principles. In addition to Plato, Johannes Kepler used these Polyhedra as the basis for his famous “Harmony of the Spheres” theory. The Hedra primitives available in Max are Tetrahedron, Cube/Octahedron, Dodecahedron/Icosahedron, and two Star types called Star1 and Star2. From these basic Polyhedra, you can create many different variations.
The Family section options determine the shape of the Hedra. Each member of a Hedra pair is mathematically related to the other member. The Family Parameters include P and Q values. These values change the Hedra between the two shapes that make up the pair. For example, if the Family option is set to Cube/Octa, then a P value of 1 displays an Octagon, and a Q value of 1 displays a Cube. When both P and Q values are set to 0, the shape becomes an intermediate shape somewhere between a Cube and an Octagon. Because the values are interrelated, only one shape of the pair can have a value of 1 at any given time. Both P and Q cannot be set to 1 at the same time.
Figure 5.16 shows each of the basic Hedra Families in columns from left to right: Tetra, Cube/Octa, Dodec/Icos, Star1, and Star2. The top row has a P value of 1 and a Q value of 0, the middle row has both P and Q set to 0, and the bottom row sets P to 0 and Q to 1. Notice that the middle row shapes are a combination of the top and bottom rows.
The relationship between P and Q can be described in this manner: When the P value is set to 1 and the Q value is set to 0, one shape of the pair is displayed. As the P value decreases, each vertex becomes a separate face. The edges of these new faces increase as the value is decreased down to 0. The same holds true for the Q value.
FIGURE 5.16
The Hedra Families with the standard shapes in the top and bottom rows and the intermediate shapes in the middle row
Tip
Altering the P and Q parameters can create many unique shapes. For each Hedra, try the following combinations: P = 0, Q = 0; P = 1, Q = 0; P = 0, Q = 1; P = 0.5, Q = 0.5; P = 0.5, Q = 0; P = 0, Q = 0.5. These represent the main intermediate objects. •
As the geometry of the objects changes, the Hedra can have as many as three different types of polygons making up the faces. These polygons are represented by the P, Q, and R Axis Scaling values. Each type of face can be scaled, creating sharp points extending from each face. If only one unique polygon is used for the faces, then only one Axis Scaling parameter is active. The Reset button simply returns the Axis Scaling value to its default at 100. For example, using the R Axis Scaling