SamuelT. wrote:

> My math abilites aren't that great either. Most of what I know about making
> functions I learned from hours of experimentation; trying out strange things
> like abs and sqr, which I didn't know anything about beforehand. Persistance
> will help you in your endeavor.
>

<smile> I planned to do that regardless.

> I hope to be adding a couple more tutorials soon. I think such things as
> noise3d and the pigment functions are very neat and have many applications.
>

I haven't quite gotten there yet. :{)

> After reading your post, I tried some experiements using your code. I tried
> all of the things that I could think of that might solve the problem, but
> the problems remain anyway. I even tried making the torus you used have
> no_shadow. I'm starting to think that it might be a bug. Strangely enough, I
> have never used csg operations with isosurfaces.
>
> Here, this will perform an intersection inside your isosurface function:
>
> function{ (your function)&(function to be intersected with) }
>
> Both functions must be within parentheses as shown. The & is like intersect
> for functions. Here is an example of this feature which makes a sphere cut
> in half by a y plane:
>
> function{ (x^2+y^2+z^2)&(y+1) }
>
> By the way, I have run into that shape you posted. It is an infinite shape,
> to be sure. I like the way you use your rgb colors, too! It's a good way to
> convert rgb colors from a paint application to pov.
>

Is it possible you could post the isosurface function for a torus so I could try
it with the intersection method you've mentioned? As an aside, how do you scale
one of these things? Every attempt I've made has resulted in very odd reactions.
Maybe there's a specific place I should put the scale command, or should I just:

function {((my function)*Scale_Factor)}
or
function {((my function)/Scale_Factor)}

I use the #/255 for my rgb quite often as pretty much half of what I do with POV
these days is destined to be used on a website somewhere. Having to use parts of
POV scenes and other items in Photoshop, I find it convenient to use the #/255
method.

David

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