Build a drone: around, bolts and standoffs

Four arms, four legs and four standoffs stand evenly around the drone. One function places a shape that many times, and every part that repeats calls it from here on; it does for the Blockly drone what the Around module does for the Rete one.

1. Arms, motors, propellers, legs and standoffs all stand evenly around the drone, so one function, around, repeats a shape count times around the upright axis. A count loop makes the angles, half a step off the axes: 45, 135, 225 and 315 degrees for four. Its first use cuts the plate's leg openings, snapped in right under the plate so the cut comes before the plate is drawn.

   • Make the function around with the inputs shape, count:
     • set angles to empty list
     • count with i from 0 to (count - 1) by 1:
       • set angles to add item(list angles, item (((i + 0.5) × 360) ÷ count), clone false)
     • return rotate shapes(shapes repeat(item shape, times count), axes repeat(item vector xyz(0, 1, 0), times count), angles angles)
   • Make the function leg openings with the inputs legs:
     • return make compound(around(cylinder(radius 6, height 3, center point xyz(52, 0, 0), direction vector xyz(0, 1, 0)), legs))
   • Snap under the block set plate to frame plate():
     • set plate to difference(shape plate, shapes [leg openings(legs)], keep edges false)
   • Run it with Run The Code.
   

2. An M3 bolt is a profile of eight points revolved into its body, with a hexagon socket cut into its head; the standoffs, the arms and the legs all use it. A standoff is a post between the plates with a bolt from below and a flipped one from above, turned back half a step so they stand between the arms.

   • Make the function m3 bolt with the inputs length:
     • set profile to [point xyz(0, -3, 0), point xyz(2.35, -3, 0), point xyz(2.75, -2.6, 0), point xyz(2.75, 0, 0), point xyz(1.5, 0, 0), point xyz(1.5, (length - 0.4), 0), point xyz(1.1, length, 0), point xyz(0, length, 0)]
     • set body to revolve(shape face from wire(shape polygon wire(profile), planar true), angle 360, direction vector xyz(0, 1, 0), copy false)
     • set socket to extrude(shape face from wire(shape ngon wire(nr corners 6, radius 1.45, center point xyz(0, -3.5, 0), direction vector xyz(0, 1, 0)), planar true), direction vector xyz(0, 2.5, 0))
     • return difference(shape body, shapes [socket], keep edges false)
   • Add a stack under the others:
     • set half back to (-180 ÷ arms)
     • set post to rotate(shape cylinder(radius 3.2, height 10, center point xyz(40, 3, 0), direction vector xyz(0, 1, 0)), axis vector xyz(0, 1, 0), angle half back)
     • set bolt to m3 bolt(8)
     • set bolt pair to rotate(shape make compound([translate(shape bolt, translation vector xyz(40, 0, 0)), translate(shape rotate(shape bolt, axis vector xyz(1, 0, 0), angle 180), translation vector xyz(40, 16, 0))]), axis vector xyz(0, 1, 0), angle half back)
     • set accent to look("accent", #f0cebb, 0.85, 0.35, #000000, #0d0e10, 4)
     • set steel to look("steel", #1c1c1e, 0.9, 0.42, #000000, #f2f2f2, 4)
     • draw any async no return(entity around(post, arms), options accent)
     • draw any async no return(entity around(bolt pair, arms), options steel)
   • Run it with Run The Code.
   

Next: one arm.