I tried this. It *is* closer. Still not "perfect" though .. :)

Thank you for the alternate method. It is something to work with.

--
Paul Vanukoff
van### [at] primenetcom


Spock wrote in message <386a33cc@news.povray.org>...
>I think the problem with the original approach is the outside of the
>object does not form part of a circle.  Even if you get the things to
>line up perfectly you will end up with an oval at best.
>
>Give the code I posted a try.  I said it doesn't work but it sure looks
>good from one angle.  BTW you don't need to rotate by "R * R * R"
>but just "R * R" instead.  I was playing around with higher orders to
>see if it smoothed things out... not worth it.
>
>You can replace the cylinders in my code with spheres if you really
>like the 3D effect.  Here is the modified code:

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Okay, this is finally the last time I try it too using what you had done
here before Paul  :-)
  With AA done on it and looking face on it seems fine, plus it's
now complete with that pair of dots found on these symbols.  What I still
don't know though is which is Ying and which is Yang, so switch the names if
need be.
  Tweaking, if any, left up to others from now on.

// Ying Yang again
camera {location < 0, 5, 0 >look_at 0}
light_source {10*y,1}

background {color rgb <1,0,0>}

#declare O_Ying=
intersection
{
 cylinder
 {
  < 0,-0.199, 0>, < 0, 0.199, 0>, 2
 }
 box
 {
  <-3,-0.2,-3>, < 3, 0.2, 0>
  inverse
 pigment {rgb <1,0,0>}
 }
 cylinder
 {
  <-1,-0.2, 0>, <-1, 0.2, 0>, 1
  inverse
 }
}

#declare O_Yang=
union
{
 object
 {
  O_Ying
 }
 cylinder
 {
  < .975,-0.2, 0>, < .975, 0.2, 0>, .975
 }
 cylinder // the white sides (black) dot
 {
  < .975,-0.21, 0>, < .975, 0.21, 0>, .25
   pigment {rgb 0}
 }
  rotate 180*y
}

#declare YingYang=
union {
union {
object {O_Ying}
 cylinder
 {
  <.975,-0.2, 0>, <.975, 0.2, 0>, .975
 }
 cylinder // the black sides (white) dot
 {
  < .975,-0.21, 0>, < .975, 0.21, 0>, .25
   pigment {rgb 1} finish {ambient 1}
 }
 pigment {rgb 0}
}

object {O_Yang pigment {rgb 1} finish {ambient 1}}
}

YingYang

// Bob

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Cool .. that seems to do the trick, as Spock has shown in p.b.a. Thanks!

--
Paul Vanukoff
van### [at] primenetcom


Adam Coffman wrote in message <386A5828.984A09DC@ipfw.edu>...
>Is it too late?  I worked out an equation for what I think you're
>trying to get.  The radius depends on the angle A in a more
>complicated way, but this seems to close up the gap.
>
>
>#declare O_Ying=
>union
>{
>    #declare R=0;
>    #while (R<1.0001)
>    #declare A=R*180;
>
>        #declare X=2*cos(radians(A))/(-3+cos(radians(A)));
>        #declare Y=0.0;
>        #declare Z=2*sin(radians(A))/(-3+cos(radians(A)));
>
>        sphere
>        {
>            <X,Y,Z>,(-1+cos(radians(A)))/(-3+cos(radians(A)))
>        }
>
>    #declare R=R+0.01;
>    #end
>}
>
>#declare O_Yang=
>object
>{
>    O_Ying
>    rotate y*180
>}
>
>
>Adam C.
>
>.......................
>
>Paul Vanukoff wrote:
>
>> I'm trying to create a ying/yang sort of image. Here is some source that
>> defines the objects. On paper it seems like it would work, but when
>> rendered, there is a nice gap between the two halves. I have messed
around
>> with different formulae, but can't get it right. Can anyone grok the
formula
>> for this?  :)
>>
>> // Source //
>>
>> #declare O_Ying=
>> union
>> {
>>     #declare R=0;
>>     #while (R<1)
>>     #declare A=R*180;
>>
>>         #declare X=1.5*cos(radians(A))+0.5;
>>         #declare Y=0.0;
>>         #declare Z=1.5*sin(radians(A));
>>
>>         sphere
>>         {
>>             <X,Y,Z>,R
>>         }
>>
>>     #declare R=R+0.01;
>>     #end
>> }
>>
>> #declare O_Yang=
>> object
>> {
>>     O_Ying
>>     rotate y*180
>> }
>>
>> // End Source //
>>
>> --
>> Paul Vanukoff
>> van### [at] primenetcom
>

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