git.scottworley.com Git - nt3d/blob - serrated.html

   1 <html>
   2   <head>
   3     <title>Serrated</title>
   4     <script type="text/javascript" src="nt3d.js"></script>
   5     <script type="text/javascript">
   6       function serrated(length, thickness, depth, serration_count, arc, steps_per_serration, edge_bevel_angle) {
   7         var tau = 2 * Math.PI;
   8         var path_length = serration_count * steps_per_serration;
   9         var path = [];
  10         for (var i = 0; i <= path_length; i++) {
  11           path[i] = [length*i/path_length,0,0];
  12         }
  13         var serration_length = length / serration_count;
  14         var serration_half_length = serration_length / 2;
  15         var serration_radius = serration_half_length / Math.sin(tau * arc / 2);
  16         var serration_max_height = Math.sqrt(serration_radius*serration_radius - serration_half_length*serration_half_length);
  17         // This emits a Sabre Grind.  TODO: Support a double bevel.
  18         // http://en.wikipedia.org/wiki/Grind#Typical_grinds
  19         // http://www.allaboutpocketknives.com/images/aapk_content/blade_bevel.JPG
  20         var edge_height = thickness / (2 * Math.tan(tau * edge_bevel_angle));
  21         function shape(i) {
  22           var serration_progress = (i % steps_per_serration) / steps_per_serration;
  23           var serration_x = serration_progress * serration_length - serration_half_length;
  24           var serration_height = serration_max_height - Math.sqrt(serration_radius*serration_radius - serration_x*serration_x);
  25           if (arc < 0) serration_height *= -1;
  26           var blade_height = depth + serration_height;
  27           return [[0,                          0,           0],
  28                   [blade_height - edge_height, 0,           0],
  29                   [blade_height,               thickness/2, 0],
  30                   [blade_height - edge_height, thickness,   0],
  31                   [0,                          thickness,   0]];
  32         }
  33         return nt3d.extrude(path, shape, [1,0,0], [0,0,1]);
  34       }
  35       var params = [["Blade length", 100],
  36                     ["Blade thickness", 2],
  37                     ["Blade depth", 10],
  38                     ["Number of serrations", 10],
  39                     ["Arc of each serration (in turns)", .2],
  40                     ["Steps per serration", 11],
  41                     ["Edge bevel angle (in turns)", .05]];
  42     </script>
  43   </head>
  44   <body onload="nt3d.framework(serrated, params)">
  45     <h1>Serrated</h1>
  46     <p>Make a serrated blade.</p>
  47   </body>
  48 </html>