cylindrical pattern creates a one unit radius cylinder along the Y axis. It is computed by:
value = 1.0-min(1, sqrt(X^2 + Z^2)) It starts at 1.0 at the origin and decreases to a minimum value of 0.0 as it
approaches a distance of 1 unit from the Y axis. It remains at 0.0 for all areas beyond that distance. This pattern
was originally created for use with
media but it may be used anywhere any pattern
may be used.