Dre wrote:
> Great, thanks for that, I'm going to have a play with that
 > later tonight!

I almost forgot...

If you can compile your own version of POV-Ray, you may be interested in 
this trick to speed up rendering *A LOT*

Load up isosurf.cpp, scroll down to the bottom, and replace the 
Evaluate_Fuction code with the code shown below.  This is basically a 
pure C code version of my Sphere Sponge isosurface function, and as you 
can imagine, can be evaluated much faster than the parsed SDL version.


DBL Evaluate_Function(FUNCTION funct, VECTOR fnvec)
{
	DBL result = -1.0;

	DBL x = fnvec[X]-0.5;
	DBL y = fnvec[Y]-0.5;
	DBL z = fnvec[Z]-0.5;

	DBL max = fabs(x);
	if (fabs(y) > max) { max = fabs(y); }
	if (fabs(z) > max) { max = fabs(z); }
	if ((fabs(x)+fabs(y)+fabs(z))/2 > max) { max = 
(fabs(x)+fabs(y)+fabs(z))/2; }

	DBL sphereScale = sqrt(x*x+y*y+z*z) / max;

	x *= sphereScale;
	y *= sphereScale;
	z *= sphereScale;

	x += 0.5;
	y += 0.5;
	z += 0.5;

	DBL size = 0.5;
	for (int level = 4; level > 0; --level)
	{
		size /= 3.0;

		DBL a = size - fabs(fmod(x,size*6.0)-size*3.0);
		DBL b = size - fabs(fmod(y,size*6.0)-size*3.0);
		DBL c = size - fabs(fmod(z,size*6.0)-size*3.0);

		if (a < b)
		{
			if (a > result) { result = a; }
		}
		else
		{
			if (b > result) { result = b; }
		}

		if (b < c)
		{
			if (b > result) { result = b; }
		}
		else
		{
			if (c > result) { result = c; }
		}

		if (c < a)
		{
			if (c > result) { result = c; }
		}
		else
		{
			if (a > result) { result = a; }
		}
	}

	if (x-1 > result) { result = x-1; }
	if (y-1 > result) { result = y-1; }
	if (z-1 > result) { result = z-1; }
	if (-x > result) { result = -x; }
	if (-y > result) { result = -y; }
	if (-z > result) { result = -z; }

	if (-x+y-z-0.5 > result) { result = -x+y-z-0.5; }
	if (+x+y-z-1.5 > result) { result = +x+y-z-1.5; }
	if (-x-y-z+0.5 > result) { result = -x-y-z+0.5; }
	if (+x-y-z-0.5 > result) { result = +x-y-z-0.5; }
	if (-x+y+z-1.5 > result) { result = -x+y+z-1.5; }
	if (+x+y+z-2.5 > result) { result = +x+y+z-2.5; }
	if (-x-y+z-0.5 > result) { result = -x-y+z-0.5; }
	if (+x-y+z-1.5 > result) { result = +x-y+z-1.5; }

    	return result;
}

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