GET PRIMITIVE |
PatchFormula |
The Get->PatchFormula command in the Model module creates a patch according to precise, user-defined formulas. Enter a system of equations defining the x, y, and z coordinates of the patch's vertices as functions of their patch coordinates u and v. These equations are composed of normal mathematical symbols and functions such as +, -, *, SIN, COS, PI, TAN, SQRT, and RAND.
There is an example of PatchFormula's use in SOFTIMAGE Custom Effects Formulæ.
Reserved Variables
These are available to you as variables for equations. For more information, see SOFTIMAGE Custom Effects Formulæ.
User Variables
If you need to use variables in your equation system which are not among the Reserved variables, you must "declare" them in this text box. If your equations use the variables radius, theta, and mu, for example, type
radius, theta, muhere. For more information, see SOFTIMAGE Custom Effects Formulæ.
Equations 0 to 9
Any number of equations may be filled in here, but each equation must be less than 40 characters. The variables U and V refer to the patch coordinates of the patch's control points. These vary from 0 to U Num - 1 in U and 0 to V Num - 1 in V. The X, Y, and Z variables are the actual coordinates you set for the control point. When not explicitly set, the default for these variables is zero. For more information, see SOFTIMAGE Custom Effects Formulæ.
U Type, V Type
These options describe what type of curve to use in u and v. Each curve may be linear, Cardinal, or B-Spline, and each may be open or closed.
U Num, V Num
These determine how many points your patch should have in the u and v dimensions.
U Tension, V Tension
These describe the curve tension of the patch in u and v.
Random Number Seed
This is the seed value for the random number generator of your computer. It is only used if you use the functions RAND or GAUSS in your equations. Different seed values produce different results.
Program Variables
Can be keyframed and used in equations.
Last updated 02-apr-1998