Refactor folding platform arm angle iron modeling

Replaces the for-loop approach with explicit left and right side angle iron modeling for the folding platform arms. Improves parametric positioning, clarifies orientation, and ensures correct mirroring and alignment with pivot plates. Also updates deck translation to sit properly on angle iron legs.

Author: dorkmo

LifeTrac-v25/mechanical_design/openscad/lifetrac_v25.scad

@@ -2482,44 +2482,79 @@ module folding_platform_assembly(fold_angle=90) {
         // When deployed: extends BACKWARD (-Y) from pivot under the deck
         // When stowed: extends UPWARD (+Z) against rear of machine
 
-        for (side = [-1, 1]) {
-            arm_x = side * arm_x_pos;
+        // Inner wall inner face X position (for aligning angle iron flush with pivot plates)
+        inner_wall_inner_face_x = TRACK_WIDTH/2 - SANDWICH_SPACING/2 - PANEL_THICKNESS;
+        
+        // Parametric positioning for angle irons relative to pivot plates
+        // Pivot bracket center X = inner_wall_inner_face_x - PLATFORM_THICKNESS/2
+        // Angle iron positioned adjacent to pivot bracket with small clearance
+        angle_iron_clearance = PLATFORM_THICKNESS / 2;  // Clearance between angle iron and pivot bracket
+        angle_iron_x_from_center = inner_wall_inner_face_x - PLATFORM_THICKNESS/2 - angle_iron_clearance;
+        
+        // Bolt hole diameter for angle iron
+        angle_bolt_hole_dia = PLATFORM_BOLT_DIA + PLATFORM_BOLT_CLEARANCE;
+        
+        // LEFT SIDE angle iron (side = -1)
+        // Positioned parametrically relative to pivot plate
+        color("DimGray")
+        translate([-angle_iron_x_from_center, pivot_y, pivot_z])
+        rotate([fold_angle, 0, 0])  // Fold rotation around X axis
+        rotate([0, 0, -90])  // Rotated so vertical leg faces outward (toward pivot bracket on left)
+        difference() {
+            linear_extrude(height=PLATFORM_ARM_LENGTH)
+            polygon([
+                [0, 0],
+                [PLATFORM_ANGLE_LEG, 0],
+                [PLATFORM_ANGLE_LEG, PLATFORM_ANGLE_THICK],
+                [PLATFORM_ANGLE_THICK, PLATFORM_ANGLE_THICK],
+                [PLATFORM_ANGLE_THICK, PLATFORM_ANGLE_LEG],
+                [0, PLATFORM_ANGLE_LEG]
+            ]);
 
-            color("DimGray")
-            translate([arm_x, pivot_y, pivot_z])
-            rotate([fold_angle, 0, 0])  // Fold rotation around X axis
-            {
-                // Angle iron L-profile extruded along arm length
-                // Rotated so vertical leg faces outward (toward pivot bracket)
-                translate([0, 0, 0])
-                rotate([0, 0, side * 90])  // Rotate profile so vertical leg faces outward toward wall
-                difference() {
-                    linear_extrude(height=PLATFORM_ARM_LENGTH)
-                    // L-shape profile - vertical leg will face outward after rotation
-                    polygon([
-                        // Start at inner corner
-                        [0, 0],
-                        [PLATFORM_ANGLE_LEG, 0],
-                        [PLATFORM_ANGLE_LEG, PLATFORM_ANGLE_THICK],
-                        [PLATFORM_ANGLE_THICK, PLATFORM_ANGLE_THICK],
-                        [PLATFORM_ANGLE_THICK, PLATFORM_ANGLE_LEG],
-                        [0, PLATFORM_ANGLE_LEG]
-                    ]);
-                    
-                    // Bolt holes at pivot bracket end (through vertical leg, near Z=0)
-                    bolt_hole_dia = PLATFORM_BOLT_DIA + PLATFORM_BOLT_CLEARANCE;
-                    for (z_off = [arm_pivot_bolt_dist - bolt_spacing, arm_pivot_bolt_dist, arm_pivot_bolt_dist + bolt_spacing]) {
-                        translate([PLATFORM_ANGLE_THICK/2, PLATFORM_ANGLE_LEG/2, z_off])
-                        rotate([0, 90, 0])
-                        cylinder(d=bolt_hole_dia, h=PLATFORM_ANGLE_THICK + 2, center=true, $fn=24);
-                    }
-                    
-                    // Bolt holes at deck end (through horizontal leg, near Z=arm_deck_bolt_dist)
-                    for (z_off = [arm_deck_bolt_dist - bolt_spacing, arm_deck_bolt_dist, arm_deck_bolt_dist + bolt_spacing]) {
-                        translate([PLATFORM_ANGLE_LEG/2, PLATFORM_ANGLE_THICK/2, z_off])
-                        cylinder(d=bolt_hole_dia, h=PLATFORM_ANGLE_THICK + 2, center=true, $fn=24);
-                    }
-                }
+            // Bolt holes at pivot bracket end
+            for (z_off = [arm_pivot_bolt_dist - bolt_spacing, arm_pivot_bolt_dist, arm_pivot_bolt_dist + bolt_spacing]) {
+                translate([PLATFORM_ANGLE_THICK/2, PLATFORM_ANGLE_LEG/2, z_off])
+                rotate([0, 90, 0])
+                cylinder(d=angle_bolt_hole_dia, h=PLATFORM_ANGLE_THICK + 2, center=true, $fn=24);
+            }
+            
+            // Bolt holes at deck end
+            for (z_off = [arm_deck_bolt_dist - bolt_spacing, arm_deck_bolt_dist, arm_deck_bolt_dist + bolt_spacing]) {
+                translate([PLATFORM_ANGLE_LEG/2, PLATFORM_ANGLE_THICK/2, z_off])
+                cylinder(d=angle_bolt_hole_dia, h=PLATFORM_ANGLE_THICK + 2, center=true, $fn=24);
+            }
+        }
+        
+        // RIGHT SIDE angle iron (side = 1)
+        // Mirrored orientation to match Left Side but mirrored
+        // Extrudes from pivot backward (same direction as Left Side)
+        color("DimGray")
+        translate([angle_iron_x_from_center, pivot_y, pivot_z])
+        rotate([fold_angle, 0, 0])  // Fold rotation around X axis
+        mirror([1, 0, 0]) // Mirror left side configuration
+        rotate([0, 0, -90])  // Same rotation as left side, then mirrored
+        difference() {
+            linear_extrude(height=PLATFORM_ARM_LENGTH)
+            polygon([
+                [0, 0],
+                [PLATFORM_ANGLE_LEG, 0],
+                [PLATFORM_ANGLE_LEG, PLATFORM_ANGLE_THICK],
+                [PLATFORM_ANGLE_THICK, PLATFORM_ANGLE_THICK],
+                [PLATFORM_ANGLE_THICK, PLATFORM_ANGLE_LEG],
+                [0, PLATFORM_ANGLE_LEG]
+            ]);
+            
+            // Bolt holes at pivot bracket end
+            for (z_off = [arm_pivot_bolt_dist - bolt_spacing, arm_pivot_bolt_dist, arm_pivot_bolt_dist + bolt_spacing]) {
+                translate([PLATFORM_ANGLE_THICK/2, PLATFORM_ANGLE_LEG/2, z_off])
+                rotate([0, 90, 0])
+                cylinder(d=angle_bolt_hole_dia, h=PLATFORM_ANGLE_THICK + 2, center=true, $fn=24);
+            }
+            
+            // Bolt holes at deck end
+            for (z_off = [arm_deck_bolt_dist - bolt_spacing, arm_deck_bolt_dist, arm_deck_bolt_dist + bolt_spacing]) {
+                translate([PLATFORM_ANGLE_LEG/2, PLATFORM_ANGLE_THICK/2, z_off])
+                cylinder(d=angle_bolt_hole_dia, h=PLATFORM_ANGLE_THICK + 2, center=true, $fn=24);
             }
         }
 
@@ -2528,11 +2563,7 @@ module folding_platform_assembly(fold_angle=90) {
         // =================================================================
         // Pivot brackets mount flush against INSIDE of inner wall panels
         // They rotate with the platform and connect angle iron to pivot pin
-        
-        // Inner wall inner face X position (facing center of machine)
-        // Inner panel outer face is at TRACK_WIDTH/2 - SANDWICH_SPACING/2
-        // Inner panel inner face is at TRACK_WIDTH/2 - SANDWICH_SPACING/2 - PANEL_THICKNESS
-        inner_wall_inner_face_x = TRACK_WIDTH/2 - SANDWICH_SPACING/2 - PANEL_THICKNESS;  // ~377mm
+        // (inner_wall_inner_face_x already calculated above in angle iron section)
 
         for (side = [-1, 1]) {
             // Bracket X position: flush against INSIDE face of inner wall
@@ -2566,7 +2597,8 @@ module folding_platform_assembly(fold_angle=90) {
         color("DarkSlateGray")
         translate([0, pivot_y, pivot_z])
         rotate([fold_angle, 0, 0])  // Same rotation as angle irons
-        translate([0, PLATFORM_ANGLE_THICK + PLATFORM_THICKNESS/2, arm_deck_bolt_dist])
+        // Deck sits on top of angle iron horizontal legs
+        translate([0, PLATFORM_THICKNESS/2, arm_deck_bolt_dist])
         rotate([90, 0, 0])  // Rotate deck to be horizontal in local coords
         platform_deck();