diff --git a/src/main.rs b/src/main.rs
index 74f723f..eaed1b3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,8 +1,10 @@
+use std::ops::Deref;
 use std::sync::Mutex;
 
 use nalgebra::Vector3;
 use scad::*;
 use constants::*;
+use selig::Airfoil;
 use selig::SeligFile;
 use selig::Point;
 use std::ops::Range;
@@ -19,13 +21,13 @@ fn main() {
 
     // cambered airfoil, used in the wing
     let wing_airfoil: SeligFile = SeligFile::parse(include_str!("../ag24.dat"));
-    println!("name {}, perim {}", wing_airfoil.get_name(), wing_airfoil.perimiter());
+    println!("name {}, perim {}", wing_airfoil.get_name(), wing_airfoil.get_points().perimiter());
     println!("desc {}", wing_airfoil.get_description().clone().unwrap_or("no desc".to_string()));
     //println!("span {:?}", points_in_range(wing_airfoil.get_points()[0..80], 0.0..1.0));
 
-    let points = &wing_airfoil.get_points()[0..80];
-    let perimeter = span_length(points);
-    let span = points_in_range(&Vec::from(points), perimeter * 0.4.. perimeter);
+    let points = wing_airfoil.get_points()[0..80].to_vec();
+    let perimeter = points.perimiter();
+    let span = points_in_range(&Vec::from(points.to_vec()), perimeter * 0.4.. perimeter);
     let points = scad::PolygonParameters::new(span);
     register_part(scad!(Polygon(points)));
 
@@ -124,7 +126,7 @@ enum SparType {
 
 /// returns a extruded airfoil with the given dimensions
 fn strut(airfoil: &SeligFile, chord: f32, width: f32, spar: &SparType) -> ScadObject {
-    let aerofoil = scad::PolygonParameters::new(airfoil.get_points().clone());
+    let aerofoil = scad::PolygonParameters::new(airfoil.get_points().to_vec());
     let shape = scad!(Polygon(aerofoil));
 
     let strut_hole = {
@@ -170,7 +172,7 @@ fn topspar_negative(airfoil: &SeligFile, chord: f32, range: Range<f32>) -> ScadO
     let points = &points[0.. points.len() / 2];
     let perimeter = span_length(points);
 
-    let span = points_in_range(&Vec::from(points), perimeter * (1.0-range.end) .. perimeter * (1.0-range.start));
+    let span = points_in_range(&points.deref().to_vec(), perimeter * (1.0-range.end) .. perimeter * (1.0-range.start));
 
     let mut mask = scad!(Union);
 
@@ -288,6 +290,7 @@ fn topwing_spar(aerofoil: &SeligFile, struts: usize, length: f32, chord: f32, ta
     wing
 }
 
+
 pub fn points_in_range(input: &Vec<Point>, range: Range<f32>) -> Vec<Point> {
     let mut last_point: Option<Point> = None;
     let mut distance: f32 = 0.0;
diff --git a/src/selig.rs b/src/selig.rs
index 87e7eb1..713ac0d 100644
--- a/src/selig.rs
+++ b/src/selig.rs
@@ -1,14 +1,16 @@
 use std::ops::Range;
+use std::ops::RangeFull;
+use std::ops::Deref;
+use std::ops::Index;
 
 use nalgebra::Vector2;
 
 pub type Point = Vector2<f32>;
-pub type Airfoil = Vec<Point>;
 
 pub struct SeligFile {
     name: String,
     description: Option<String>,
-    data: Airfoil,
+    data: Vec<Point>,
 }
 
 impl SeligFile {
@@ -33,7 +35,7 @@ impl SeligFile {
         }
     }
 
-    pub fn get_points(&self) -> &Airfoil {
+    pub fn get_points(&self) -> &Vec<Point> {
         &self.data
     }
 
@@ -47,12 +49,13 @@ impl SeligFile {
 
 }
 
-impl Airfoil {
-    pub fn perimiter(&self) -> f32 {
-        self.span_length(&self.get_points()[..])
-    }
+pub trait Airfoil {
+    fn perimiter(&self) -> f32;
+}
 
-    fn span_length(&self, points: &[Point]) -> f32 {
+impl Airfoil for Vec<Point> {
+    fn perimiter(&self) -> f32 {
+        let points = self;
         let mut last_point: Option<Point> = None;
         let mut distance: f32 = 0.0;
         for point in points {
@@ -64,3 +67,16 @@ impl Airfoil {
         distance
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::{Airfoil, SeligFile};
+
+    #[test]
+    fn full_perimiter() {
+        let airfoil = SeligFile::parse(include_str!("../ag24.dat"));
+        let airfoil = airfoil.get_points();
+
+        assert_ne!(airfoil.perimiter(), airfoil[0..80].to_vec().perimiter());
+    }
+}