Added a model of an epicyclic.

model/epicyclic.scad

@@ -0,0 +1,53 @@
+// epicyclic.scad
+
+// an epicyclic gearbox, similar to a Rohloff or Shimano Nexus 11
+// dimensions in millimetres, mostly from https://www.rohloff.de/en/service/handbook/speedhub/technical-data
+// (c) Simon Brooke 2025; CC-BY-SA
+
+include <Library/SprocketGenerator2/files/Sprocket_Generator_v2_example_10.scad>
+
+module epicyclic (olnd=135, disc=1) {
+    
+    body_width=116; 
+    spoke_flange_width=3.2;
+    
+    // axle
+    color("grey")
+    cylinder(h=(olnd + 12), r=6, center=true);
+    
+    // locknuts, etc
+    color("black")
+    cylinder(h=olnd, r=15, center=true);
+    
+    // epicyclic body
+    color("red")
+    cylinder(h=body_width, r=46, center=true);
+
+    // spoke flanges. TODO: yes, they need spoke holes.
+    translate([0, 0, (body_width/2) - spoke_flange_width])
+        color("red")
+        cylinder(h=spoke_flange_width, r=54);
+    
+    translate([0, 0, 0 - (body_width/2)])
+        color("red")
+        cylinder(h=spoke_flange_width, r=54);
+
+    // primary chain sprocket, obvs
+    translate([0, 0, 3 - (olnd/2)])
+        color("grey")
+        sprocket(teeth=20, roller=7.9, pitch=12.7);
+        
+    translate([0, 0, 0 - ((body_width/2) - spoke_flange_width)])
+        color("grey")
+        sprocket(teeth=30, roller=7.9, pitch=12.7);
+        
+    // disc brake, if present. TODO: details of disc spider
+    if (disc==1) {
+        translate([0, 0, (olnd/2) - 7])
+        color("silver")
+        cylinder(h=1.5, r=75);
+    }
+}
+
+// rotate([90, 0, 0])
+//   epicyclic();