isosurface { //------------------------------------------------------------- function{ f_helical_torus ( x,y,z, 1 , //P0: major radius, 1 , //P1: number of winding loops 1, //P2: Twistiness of winding. When zero, each winding loop is separate. // When set to one, each loop twists into the next one. When set to two, each loop twists into the one after next 0.5, //P3: Fatness of winding? 0.0, //P4: Threshold. Setting this parameter to 1 and the threshold to zero has s similar effect // as setting this parameter to zero and the threshold to 1 0.0, //P5 : Negative minor radius? Reducing this parameter increases the minor radius of the central torus. // Increasing it can make the torus disappear and be replaced by a vertical column. // The value at which the surface switches from one form to the other depends on several other parameters 0, //P6: Another fatness of winding control? 1, // P7: Groove period. Increase this for more grooves 0.17, // P8: Groove amplitude. Increase this for deeper grooves 2 // P9: Groove phase. Set this to zero for symmetrical grooves ) } contained_by {box {<-1.5,-1,-1.5>,<1.5,1,1.5>}} max_gradient 50 texture{ pigment{ color rgb <1,0.8,0.6>} finish { specular 0.1 roughness 0.1 phong 0.2 } } rotate<0,0,0> scale 1 translate< 0,1.01, 0> } // end of isosurface -------------------------------------------------------