POV-Ray Geometric Shapes

torus = tube, ring

torus
general syntax:

torus{ r_major,r_minor
        texture{ ... ... }
        }

In this definition r_major is the big radius and r_minor is the little radius. The torus is placed by default in the xz-plane (horizontal) with the y-axis as the axis of it's rotation symmetry.
The radius of the outline:
r_total= r_major +r_minor .
The radius of the center hole:
r_inside= r_major -r_minor .

If another position is needed the torus must be transformed by "rotate< , , >" and "translate< , , >" .

Example here:

//------------ the yellow torus in the middle:
torus{ 1.0,0.25 scale <1,1,1>
       texture{ pigment{ color rgb<1,0.65,0>}
                finish { phong 1}
              }
       rotate<0,0,0> translate<0,0,0>
     }
//------ golden torus right in the background:
torus{ 1.0,0.25 scale <1,3,1>
       texture{ Polished_Chrome
                pigment{ color rgb<1,0.8,0>}
                normal { bumps 0.5 scale 0.15}
                finish { phong 1 }
              }
       rotate<90,0,0> translate<4,3,2>
     }
//--------- the flat silver ring on the left:
torus{ 1.0,0.65 scale <1.5,0.33,1>
       texture{ Polished_Chrome
                pigment{ color rgb<1,1,0.5>}
                normal { bumps 0.5 scale 0.15}
                finish { phong 1}
              }
       rotate<0,0,90> translate<-1,3,-2>
     }
//--------------------------------------------