git.scottworley.com Git - nt3d/blob

1 <html>

2 <head>

3 <title>The Thing the Rostock Was Printing in Make Magazine</title>

     <script type="text/javascript" src="nt3d.js"></script>

5 <script type="text/javascript">

6 function pointy_sin(x) {

7 // Similar to sin(x*pi) over the range [-1,1],

8 // but with more movement towards the extremes.

9 // https://plus.google.com/101508799331795210529/posts/Yg7LmV8BpTw

         return 3.7*x + (Math.log(1-.95*x)-Math.log(.95*x+1));

11 }

12 function rmm(params) {

13 var tau = Math.PI*2;

14 var path = [];

15 // Short arc

16 for (var i = 0; i < params.steps_along; i++) {

17 var progress = i/params.steps_along;

18 var x_separation = Math.cos(progress*tau/2)*params.base_separation;

19 var y_offset = -Math.sin(progress*tau/4)*params.base_offset;

20 var y_arc = Math.sin(progress*tau)*params.width;

21 var z_arc = -Math.cos(progress*tau)*params.short_arc_height + params.short_arc_height;

22 path.push([x_separation, y_offset + y_arc, z_arc]);

23 }

24 // Tall arc

25 for (var i = 0; i < params.steps_along; i++) {

26 var progress = i/params.steps_along;

27 var x_arc = -Math.cos(progress*tau*1.5)*params.base_separation;

28 var y_offset = -Math.cos(progress*tau/4)*params.base_offset;

29 var y_twist = -pointy_sin(progress*2 - 1)*params.width/2;

30 var z_arc = -Math.cos(progress*tau)*params.tall_arc_height + params.tall_arc_height;

31 path.push([x_arc, y_offset + y_twist, z_arc]);

32 }

33 return nt3d.closed_extrude(

34 path,

35 nt3d.circle(params.tube_width, params.steps_around),

36 nt3d.shapenormals_from_closed_path(path),

37 nt3d.pathnormals_from_point(path, [0,0,0]));

38 }

39 var params = [["base_separation", 30],

40 ["base_offset", 10],

41 ["width", 40],

42 ["short_arc_height", 60],

43 ["tall_arc_height", 80],

44 ["tube_width", 10],

45 ["steps_along", 70, "Steps Along Each Arc"],

46 ["steps_around", 12]];

47 </script>

48 </head>

49 <body onload="nt3d.framework(rmm, params)">

50 <h1>The Thing the Rostock Was Printing in Make Magazine</h1>

     <p><a href="http://www.flickr.com/photos/jcrocholl/8065968929/sizes/l/in/photostream/">This thing</a>.</p>

52 <!-- My notes after staring at it:

53 x y z

54 1 0 0 Bottom front

55 .5 1 .5s 1/4 up short arc

56 0 0 s Top of short arc

57 -.5 -1 .5s Coming down short arc

58 -1 0 0 Bottom back

59 1 .33 .5t 1/4 up long arc

60 0 0 t Top of tall arc

61 -1 -.33 .5t Coming down tall arc

62 1 0 0 Bottom front (Repeated from above)

64 x = cos over 1/2 period for short arc, -cos over 1.5 periods for tall arc

65 y = sin over 1 period for short arc, sin/3 over 1 period for tall arc

66 z = -cos over 1 period for short arc, -cos over 1 period for tall arc

67 -->

68 </body>

69 </html>