topeak-mtx-tortec-expeditionrack-adapter: wip $reverse_sign

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/topeak-mtx-tortec-expeditionrack-adapter.scad b/topeak-mtx-tortec-expeditionrack-adapter.scad
index 9d41488852c56d4baea6132d194f544f7f4085e9..95cdae27a5e283c7aac28216768156430e8e90e5 100644 (file)
--- a/topeak-mtx-tortec-expeditionrack-adapter.scad
+++ b/topeak-mtx-tortec-expeditionrack-adapter.scad
@@ -149,7 +149,7 @@ module MainExtrude(z){
     children();
 }
 module RackShear(){
-  s = rack_shear_ratio;
+  s = rack_shear_ratio * $reverse_sign;
   multmatrix([ [ 1, 0,  0, 0 ],
               [ 0, 1, s , 0 ],
               [ 0, 0,  1, 0 ],
@@ -269,6 +269,9 @@ module Principal(){
 
   $foreaftmaint_rail_z = brk_block_z/2 + $foreaftmaint_dz - foreaftmaint_y_slop;
 
+  translate([0,0,brk_block_z/2])
+  mirror([0,0, $reverse_sign > 0 ? 0 : 1])
+  translate([0,0,-brk_block_z/2])
   difference(){
     union(){
       MainExtrude(main_sz_lhs_z){
@@ -378,13 +381,15 @@ module RackForDemo(){ ////toplevel
 
 module Front(){ ////toplevel
   // xxx elevation is wrong
-  Principal($elevation_nominal=
+  Principal($reverse_sign = +1,
+           $elevation_nominal=
       elevation_of_bolt_for(rear_to_cross_rail + rear_bolt_to_front_bolt),
            $foreaftmaint_dz= front_to_cross_rail);
 }
 
 module Rear(){ ////toplevel
-  Principal($elevation_nominal=
+  Principal($reverse_sign = +1,
+           $elevation_nominal=
       elevation_of_bolt_for(rear_to_cross_rail),
            $foreaftmaint_dz= rear_to_cross_rail);
 }