On 11/29/2016 6:07 AM, omniverse wrote:
> Mike Horvath <mik### [at] gmailcom> wrote:
>> On 11/28/2016 6:42 PM, Mike Horvath wrote:
>>> Clipka gave me these formulas to generate a cylindrical isosurface.
>>>
>>> #declare fL = function(x,y,z) {y*100}
>>> #declare fC = function(x,y,z) {sqrt(x*x+z*z)*128}
>>> #declare fH = function(x,y,z) {atan2d(x,z)}
>>>
>>> What would be a formula for a sphere? L should be latitude, H longitude,
>>> and C radius.
>>>
>>> Thanks.
>>
>> Would I use atan(x,y) for L? This produces values between -90..90
>> degrees, correct? Or should it be atan(z,y)?
>
> I sure don't know enough to tell you much of anything, the sphere equation is
> something like:
>
> function(x,y,z,r) {(pow(x,2)+pow(y,2)+pow(z,2))-pow(r,2)}
>
> There's also the inbuilt function called internal (61) used by functions.inc for
> its f_sphere(x,y,z,r) where r is radius. Hopefully I got this right, please
> don't count on it!
>
> Bob
>
> P.S. I was trying, rather clumsily, to get the idea of what you might have been
> trying to make and only succeeded in creating strange isosurface shapes. Some
> were a partial sphere with both a vertical and horizontal cut across it,
> thinking I changed to atan(y) and atan2(x,z) but I got lost in the fascination
> of new shapes.
>
>

Thanks for trying, at least.

:)

Mike

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