Wlodzimierz ABX Skiba wrote:
> 
> Remco de Korte wrote in message <3A5990BE.2E6AC598@onwijs.com>...
> >If I have a sphere with radius 1 intersected by a cylinder with radius .5, with
> >an axis in the z-direction through point <.75,0>
> 
> on x-y plane, right ?

Eh.. no, in 3D space actually.
> 
> > how can I calculate the points
> > on the curve where these two intersect?
> 
> input
>   R1=1
>   R2=.5
>   H=.75
> sphere equatiuon
>   x^2 + y^2 + z^2 = R1^2
> cylinder equation
>   x^2 + (y-H)^2 = R2^2
> we substract both equations side by side to remove x^2
>   y^2 + z^2 - (y-H)^2 = R1^2 - R2^2
> after reduction we obtain equation for y
>   y = ( R1^2 - R2^2 + H^2 -z^2 ) / ( 2 * H )
> using cylinder equation you can calculate two values of x
>   x = +/- sqrt( R2^2 - (y-H)^2 )

Thank you, I'll go try this out.
> 
> I have not tested it but I hope it'll help you
> Should be very interesting to write parametric equation for it
> to distribute evenly points on it
> 

That's my next step. I think I can handle that but probably by approximation.

> ABX

Remco

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