From 87a0c3431e76e72e5037c4b9e652238f43421074 Mon Sep 17 00:00:00 2001
From: Simon Brooke <simon@journeyman.cc>
Date: Wed, 10 Sep 2025 18:19:03 +0100
Subject: [PATCH] Subframe now switchable between aluminium and carbon
 versions; TODO carbon variant lacks its wheel leg.

---
 model/hull.scad     | 22 ++++++++++++----------
 model/subframe.scad | 34 +++++++++++++++++++++++++++++++---
 model/tricycle.scad |  4 +---
 3 files changed, 44 insertions(+), 16 deletions(-)

diff --git a/model/hull.scad b/model/hull.scad
index cf08e2a..ba189b5 100644
--- a/model/hull.scad
+++ b/model/hull.scad
@@ -34,32 +34,34 @@ module hull_i() {
 
 module hull() {   
     intersection() {
-        translate([2000,0,0])
+        translate([2500,0,500])
             rotate([180, 90, 0])
-            scale([20, 16, 20])
+            scale([20, 15.5, 20])
             rotate_extrude()
             //rotate([ 0, 90, 0])
             import("library/hull-volume-of-rotation.svg");
         
-        translate([-900,0, -110])
+        translate([-400,0, 350])
         rotate([0, 90, 0])
-            prismoid(size1=[1100, 1000], 
+            prismoid(size1=[900, 1000], 
                     size2=[400, 600], 
                     height=3000);   
     }
         
     rotate([0,90,0])
-        translate([0,0,-2070])
+        translate([-500,0,-1570])
         difference() {
             skin(
-                [ellipse($fn=64,r=[350,30],center=true),
-                 ellipse($fn=64,r=[430,340],center=true)], z=[0,1200],
+                [ellipse($fn=64,r=[350,30]),
+                 ellipse($fn=64,r=[430,340])], 
+                 z=[0,1200],
                 slices=40,sampling="length",method="reindex");
             skin(
-                [ellipse($fn=64,r=[344,24],center=true),
-                 ellipse($fn=64,r=[424,334],center=true)], z=[-1,1201],
+                [ellipse($fn=64,r=[344,24]),
+                 ellipse($fn=64,r=[424,334])],
+                 z=[-1,1201],
                 slices=40,sampling="length",method="reindex");
         }
 }
 
-hull();
\ No newline at end of file
+hull();
diff --git a/model/subframe.scad b/model/subframe.scad
index 5286e1d..1a79ee0 100644
--- a/model/subframe.scad
+++ b/model/subframe.scad
@@ -9,7 +9,6 @@ include <SprocketGenerator2/files/Sprocket_Generator_v2_example_10.scad>
 include <chainset.scad>
 include <epicyclic.scad>
 
-
 module subframe_cycleparts(rim=451, chainring_teeth=82, crank=140) {
         // wheel
     translate([0, 382, 93])
@@ -30,7 +29,8 @@ module subframe_cycleparts(rim=451, chainring_teeth=82, crank=140) {
         epicyclic();   
 }
 
-module subframe (rim=451, chainring_teeth=82, crank=140) {
+
+module aluminium_subframe (rim=451, chainring_teeth=82, crank=140) {
     // front leg (supports cross-shaft, epicyclic, motor
     translate([-25, 820, -60])
         color("silver")
@@ -64,5 +64,33 @@ module subframe (rim=451, chainring_teeth=82, crank=140) {
     subframe_cycleparts(rim, chainring_teeth, crank);    
 }
 
+/**
+ * this is more or less right. I need to sculpt out a depression for
+ * the secondary chain, and make a bracket to hold the epicyclic and
+ * motor.
+ */
+module carbon_subframe(rim=451, chainring_teeth=82, crank=140) {
+    translate([-25, 0, 0])
+    color("black")
+        difference() {
+            rotate([90, 0, 90])
+                linear_extrude( height=50)
+                    polygon([[1020, 306], [680, 400], [150,408], [50, 0], [1020, 0]]);
+            translate([-26, 382, 93])
+                rotate([90,0,90])
+                cylinder( h=100, r=rim * 0.61);
+        }
+    
+    subframe_cycleparts(rim, chainring_teeth, crank);    
+}
+
+module subframe( structure="carbon", rim=451, chainring_teeth=82, crank=140) {
+    if (structure == "carbon") {
+        carbon_subframe(rim=rim, chainring_teeth=chainring_teeth, crank=crank);
+    } else {
+        aluminium_subframe(rim=rim, chainring_teeth=chainring_teeth, crank=crank);
+    }       
+}
+
+// subframe( structure="carbon");
 
-// subframe(chainring_teeth=90, crank=140);
diff --git a/model/tricycle.scad b/model/tricycle.scad
index 75f8ed4..fc5aa83 100644
--- a/model/tricycle.scad
+++ b/model/tricycle.scad
@@ -4,11 +4,9 @@
 
 // Top level final rendering
 
-include <BentSim/Library/Velo_rider.scad>
-
 include <subframe.scad>
 include <fourbar.scad>
-// include <hull.scad>
+//include <hull.scad>
 
 rotate([0, 0, 270])
 translate([0, 1200, 180])