//********************************************************
//                    Horizontal Sundial
//               NASS Sundial Design Tutorials
//                    Part 1 Sundial Base
//					Robert L. Kellogg, Ph.D.
//				          1 Dec 2019
//
//        This design is part of the creative commons
//********************************************************

/* We're going to create the base of a sundial.  Three
   variation are given: a circular sundial and a dial base
   with 6 or 8 sides (hexagon or octagon).
   
   We'll make the sundial base with a slight taper of the
   sides. This is just a bit of simple esthetics.  
*/  

echo("Part-1 NASS Sundial Base");  //NASS Tutorial

// ----------------------------------------------------
// ---------------  Sundial Parameters ----------------
// ----------------------------------------------------
// Note:  base units are in mm and angles in degrees

shape   = "octagon";    // "circular"  dial base 
                        // "hexagon"   dial base
                        // "octagon"   dial base
                            
dial_btm    = 78;       //dial base(~3")         mm
dial_top    = 75;       //dial base (taper top)  mm
dial_hght   = 3;        //dial base height       mm


// ----------------------------------------------------
// ------------  Main Program Starts Here -------------
// ----------------------------------------------------
if(shape=="circular") {
    echo("shape",shape);
    minangle = 3;
    sundial_base(minangle,turn=0);
}
if(shape=="octagon") {
    echo("shape",shape);
    minangle = 45;
    sundial_base(minangle,turn=45/2);
}
if(shape=="hexagon") {
    echo("shape",shape);
    minangle = 60;
    sundial_base(minangle,turn=0);
}
         
// ----------------------------------------------------
// ----------- Procedure Modules Start Here -----------
// ----------------------------------------------------   
module sundial_base(mini,turn) {
    $fa = mini;
    rotate([0,0,turn])  //notice no ';' since rotate cylinder
    cylinder($fa,h=dial_hght,d1=dial_btm,d2=dial_top);
    
    //we use the built-in procedure called cylinder, using
    //the options to define a top and bottom size.
    
    //$fa sets the number of degrees for each cylinder segment
    // circular $fa=3, hexagon $fa=45, octagon $fa=60
    
    //'center=false' still puts the cylinder center at xy = (0,0)
    //but the bottom of the cylinder rests at z=0 (that is, it
    //sets on the ground of the xy plane.
    
    //the size of the sundial base could have been passed as
    //variables, such as calling
    //  sundial_base(dial_hght,dial_btm,dial_top,mini,turn);
    //and the procedure could be
    //  sundial_base(hght,btm,top,mini,turn);
    
    //Notice that the rotate operator function occurs before the
    //object it acts upon.  Hence rotate() appears in the line 
    //above the cylinder object and has no ";".  Only the object
    // cylinder();  gets the ";"
}