Hi all,

Steven Worley has source code available for his cellular basis function. See www.texturingandmodeling.com

Is this something that could be incorporated as another function to call in procedural materials, similar to fnoise and others?

The copyright (see below) would seem to allow for use of the code in a pretty open manner.

Regards,

-Jack de Valpine

/* Copyright 1994, 2002 by Steven Worley

This software may be modified and redistributed without restriction

provided this comment header remains intact in the source code.

This code is provided with no warrantee, express or implied, for

any purpose.

A detailed description and application examples can be found in the

1996 SIGGRAPH paper "A Cellular Texture Basis Function" and

especially in the 2002 book "Texturing and Modeling, a Procedural

Approach, 3rd edition." There is also extra information on the web

site http://www.worley.com/cellular.html .

If you do find interesting uses for this tool, and especially if

you enhance it, please drop me an email at steve@worley.com. */

/* Worley()

An implementation of the key cellular texturing basis

function. This function is hardwired to return an average F_1 value

of 1.0. It returns the <n> most closest feature point distances

F_1, F_2, .. F_n the vector delta to those points, and a 32 bit

seed for each of the feature points. This function is not

difficult to extend to compute alternative information such as

higher order F values, to use the Manhattan distance metric, or

other fun perversions.

<at> The input sample location. <max_order> Smaller values compute faster. < 5, read the book to extend it.

<F> The output values of F_1, F_2, ..F[n] in F[0], F[1], F[n-1]

<delta> The output vector difference between the sample point and the n-th

closest feature point. Thus, the feature point's location is the

hit point minus this value. The DERIVATIVE of F is the unit

normalized version of this vector.

<ID> The output 32 bit ID number which labels the feature point. This

is useful for domain partitions, especially for coloring flagstone

patterns.

This implementation is tuned for speed in a way that any order > 5

will likely have discontinuous artifacts in its computation of F5+.

This can be fixed by increasing the internal points-per-cube

density in the source code, at the expense of slower

computation. The book lists the details of this tuning. */

## ···

--

# John E. de Valpine

# president

#

# visarc incorporated

# http://www.visarc.com

#

# channeling technology for superior design and construction