Star  

We start with a "box". To get a clearly defined length of the rays we scale the box by the square root of 2. (Then the diagonals of it's surfaces have a length of 2 units!)

  box { <-1,-1,-1>,< 1,1,1> 
        scale <1,1,1>*sqrt(2)
      }

We rotate the box around the z axis by 45 degrees.

  box { <-1,-1,-1>,< 1,1,1> 
        scale <1,1,1>*sqrt(2)
        rotate<0,0,45>
      }

Then the box is scaled in y direction and after this it is turned around the x axis by 45 degrees. We use the declare statement to make this shape now to a new object called "Ray_Profile".

  #declare Ray_Profile =
   box { <-1,-1,-1>,< 1,1,1> 
        scale <1,1,1>*sqrt(2)
        rotate<0,0,45>
        scale <1,0.36,1> 
      }

The new object is now mirrored at the xy plane in z direction by "scale<1,1,-1>". Then we make an intersection of the original shape and it's mirror image.

 intersection{
   object{ Ray_Profile } 
   object{ Ray_Profile scale<1,1,-1>}
   }

To be able to make also stars with an odd number of rays we need to subtract ( = intersection with the inverse shape) a box to get rid of the left part of our ray shape. This shape now we declare as a new object called "'Ray".

#declare Ray =
 intersection{
   object{ Ray_Profile }  
   object{ Ray_Profile scale<1,1,-1>}
   box{<-2,-1,-1>,<0,1,1> inverse}
   }

The rays of a star were arranged finally by a while loop rotating them around the y axis. For the right image the rays were made more slender by applying " scale<1,0,5,0.5> ".
The resulting star shape has a radius of 2 units.

union{
 #local Nr = 0;     // start 
 #local EndNr = 5;  // end
 #while (Nr < EndNr) 
 object{Ray rotate<0,Nr*360/EndNr,0>}
 #local Nr = Nr + 1;// next Nr
 #end // ------------- end of loop 
rotate<0,0,0> 
translate<0,0,0>  
} // end of union

Click here for the complete description
of the scene for POV-Ray:
".txt"-file or ".pov"-file