// hole size = given (also for use with other parts
// so based on the material thickness (3.0mm +/- 0.3mm) the width
// of pegs should vary
mat = 3;        // material setting
kerfoffset = 0.15; // half of the laser kerf
// material spacing (the LEGO units)
hole = 5;         // hole size
plateunit = 25;   // distance between holes
ring = 10; 
beam = 8;// 
// settings for locking depending on material flexibility
lock = 0.8;
gap = 1.5;
$fn=30; // render
// the parts to render
projection(){
    //anglebeam(90,0,90,1,0);
    basic(5);
}
module anglebeam(angle2,angle1,angle3,units,angle){
    translate([0,0,0])onebeam(angle2,angle1,units);
    translate([0,plateunit,0])rotate([0,0,angle])onebeam(angle3,angle2,units);
}
module onebeam(angle2,angle1,units){
translate([0,plateunit,0])rotate([0,0,angle1])basic(units);
translate([-beam/2-kerfoffset/2,ring/2-hole/2,0])cube([beam+kerfoffset,plateunit-ring/2,mat]);
translate([0,0,0])rotate([0,0,angle2])basic(units);
}
//translate([-mat/2,0,ring/2+mat])rotate([0,90,0])basic(1);
module basic(units){
    difference(){
        union(){
        cylinder(d=ring+kerfoffset,h=mat);
        translate([hole/2,-0.5*(sqrt(hole^2-mat^2)+kerfoffset),0])cube([ring/2-hole/2+units*mat+lock+kerfoffset/2,sqrt(hole^2-mat^2)+kerfoffset,mat]);
        translate([ring/2+units*mat+lock/2,sqrt(hole^2-mat^2)/2,0])cylinder(d=lock+kerfoffset,h=mat);
        translate([ring/2+units*mat+lock/2,-sqrt(hole^2-mat^2)/2,0])cylinder(d=lock+kerfoffset,h=mat);
        }
    translate([0,0,-0.01])cylinder(d=hole-kerfoffset,h=mat+0.02);  // central hole
    translate([ring/2,0,-0.01])cylinder(d=gap-kerfoffset,h=mat+0.02); 
    translate([ring/2,-0.5*(gap-kerfoffset),-0.01])cube([ring/2-hole/2+units*mat+lock,gap-kerfoffset,mat+0.02]);
        translate([ring/2,0,-0.01])cylinder(d=gap-kerfoffset,h=mat); 
    }
}

//translate([-sqrt(hole^2-mat^2)/2,-mat/2,0])cube([sqrt(hole^2-mat^2),mat,10]); // test piece