Are you sure?

function {noise3d(x ^0.5, y, z)}, I know,  is symmetric about the x=0
plane.
function {noise3d(x^3.0, y, z)}, I will bet, behaves correctly, and has
a kind of symmetry like the curve y=x^3.

There is something "more wrong" here.  If Ron were correct, then x^3
would also be symmetric about x=0.

david sharp wrote:

> david sharp <dsh### [at] interportnet> wrote in message
> news:387a0473@news.povray.org...
> >
> > Ron Parker <ron### [at] povrayorg> wrote in message
> > news:387a0293@news.povray.org...
> > > On Mon, 10 Jan 2000 10:55:52 -0500, david sharp wrote:
> > > >The isosurface stuff converts x to absolute value of x
> > > >before trying to use the ^. This is just to avoid many floating
> > > >point errors.  The isosurface code does the same conversion
> > > >before applying sqrt() or ln().
> > >
> > > Does it only do that for fractional exponents, or does it also
> > > do it for odd integer exponents?
> >
> > Always.
>
> No, not always. (I should have actually checked before replying)
> there is a ffloor test to distinguish integers from fractions.

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