align and rotate part to sloped segment

$fn=15;
/* [circle offsets] */
crcXoff=0;//[-20:1:20]
crcYoff=0;//[-20:1:20]
crctopXoff=0;//[-20:1:20]
crctopYoff=0;//[-20:1:20]
/* [segment height, bottom and top circle radiuses] */
seghght=10;//[0:1:20]
crcrad=10;//[0:1:20]
crctoprad=15;//[5:1:30]
/* [rotation angles] */
linerotAngle=0;//[-180:15:180]
fixRotAngle=0;//[-180:1:180]
// 2 circles to simulate segment
translate([0+crcXoff,crcYoff,0]) { %cylinder(h=.1,r=crcrad);
    color("blue") hull(){  translate([crcrad,0,.1])cube(.1,true); translate([-crcrad,0,.1])cube(.2,true);  }
    color("blue") hull(){  translate([0,crcrad,.1])cube(.1,true); translate([0,-crcrad,.1])cube(.2,true);  } }
translate([0+crctopXoff,crctopYoff,seghght]) { %cylinder(h=.1,r=crctoprad);
    color("blue") hull(){translate([crctoprad,0,0])cube(.2,true); translate([-crctoprad,0,0])cube(.2,true);}
    color("blue") hull(){translate([0,crctoprad,0])cube(.2,true); translate([0,-crctoprad,0])cube(.2,true);} }
// red line connecting points on circles at various rotation angles
color("red")hull(){ translate([crcXoff,crcYoff])       rotate(linerotAngle) translate([crcrad,0,0])          cube(0.2,true);
                    translate([crctopXoff,crctopYoff]) rotate(linerotAngle) translate([crctoprad,0,seghght]) cube(0.2,true); }
module part() { // centered, X aligned, cyan top -X
    //translate([seghght/2-1.5,0,.5])color("cyan")cube([1,2,1],true); translate([-.5,0,.5])color("grey")cube([seghght-2-1,2,1],true); translate([0,0,-.5])color("yellow")cube([seghght-2,2,1],true);
    translate([-seghght/2+1.5,0,.5])color("cyan")cube([1,2,1],true); translate([.5,0,.5])color("grey")cube([seghght-2-1,2,1],true); translate([0,0,-.5])color("yellow")cube([seghght-2,2,1],true);
}

rotMulti=cos(PI*linerotAngle/180);
rotateFromTo(   p1=[crcrad*cos(linerotAngle)+crcXoff*rotMulti,crcrad*sin(linerotAngle)+crcYoff*rotMulti,0],
                p2=[crctoprad*cos(linerotAngle)+crctopXoff*rotMulti,crctoprad*sin(linerotAngle)+crctopYoff*rotMulti,seghght] )
    {
        // prerotate part to align with segment surface
//        rotate([0,-90,fixRotAngle-90])  // if part's top in +X
        rotate([0, 90,fixRotAngle+90])  // if part's top in -X
            part();
    };
module rotateFromTo(p1,p2){ // rotates part to align with 2-point vector line and moves to it's mid
    translate((p1+p2)/2)                                                            // move to mid
    rotate([-acos((p2[2]-p1[2])/norm(p1-p2)),0,-atan2(p2[0]-p1[0],p2[1]-p1[1]) ])   // rotate to slope
        children();
}