diff --git a/src/main.rs b/src/main.rs
index 3c3f278..785feb2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -33,8 +33,10 @@ fn main() {
     parts.append(wing_transform.parts.as_mut());
 
     // "fuselage"
+    let mut fuselage = spar(LENGTH);
     scad_file.add_object(scad!(Rotate(-90.0, vec3(0.0, 0.0, 1.0));
-        spar(LENGTH, false)));
+        fuselage.visualization));
+    parts.append(fuselage.parts.as_mut());
 
     // rudder
     let mut rudder = scad!(Rotate(90.0, vec3(1.0, 0.0, 0.0)));
@@ -319,11 +321,10 @@ fn topspar_negative(airfoil: &SeligFile, chord: f32, range: Range<f32>) -> ScadO
     mask
 }
 
-// TODO: shift to trangle design
-fn spar(length: f32, center: bool) -> ScadObject {
+fn spar(length: f32) -> Construct {
     let mut spar = scad!(Union);
 
-    //register_part(scad!(Square(vec2(length, SPAR_SIDE_WIDTH * 3.0))));
+    let parts = vec![scad!(Square(vec2(length, SPAR_SIDE_WIDTH * 3.0)))];
 
     let top = centered_cube(vec3(SPAR_SIDE_WIDTH, length, CARDBOARD_WIDTH), (true,false,false));
     let mut left = centered_cube(vec3(SPAR_SIDE_WIDTH, length, CARDBOARD_WIDTH), (false,false,false));
@@ -335,7 +336,7 @@ fn spar(length: f32, center: bool) -> ScadObject {
     spar.add_child(right);
     spar.add_child(top);
 
-    spar
+    Construct { visualization: spar, parts }
 }
 
 fn lerp(a: f32, b: f32, x: f32) -> f32 {