diff --git a/notes.md b/notes.md
index 35f0f998..40c526fb 100644
--- a/notes.md
+++ b/notes.md
@@ -1,5 +1,9 @@
 # Kiri:Moto todo
 
+NEXT
+- contour outside part boundaries
+- fdm first level height render
+
 ## `C` cosmetic, `F` functional, `P` performance, `B` bug fix
 
 * `F` detect and report slow framerates
diff --git a/package.json b/package.json
index c4f13f6f..4f9a45b9 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "grid-apps",
-    "version": "2.3.D5",
+    "version": "2.3.D6",
     "description": "grid.space 3d slice & modeling tools",
     "author": "Stewart Allen <sa@grid.space>",
     "license": "MIT",
diff --git a/src/add/array.js b/src/add/array.js
index 8a0202c7..4284973b 100644
--- a/src/add/array.js
+++ b/src/add/array.js
@@ -6,7 +6,7 @@
     var AP = Array.prototype;
 
     /** ******************************************************************
-     * array prototype helpers
+     * Array prototype helpers
      ******************************************************************* */
 
      if (!AP.flat) {
@@ -148,7 +148,7 @@
     };
 
     /** ******************************************************************
-     * string prototype helpers
+     * String prototype helpers
      ******************************************************************* */
 
     String.prototype.reverse = function() {
@@ -167,4 +167,13 @@
         return Math.max(min,Math.min(max,val));
     };
 
+    /** ******************************************************************
+     * Number static helpers
+     ******************************************************************* */
+
+    Number.prototype.round = function(digits) {
+        const pow = Math.pow(10,digits || 3);
+        return Math.round(this.valueOf() * pow) / pow;
+    };
+
 })();
diff --git a/src/geo/polygon.js b/src/geo/polygon.js
index 35f0d322..810d412f 100644
--- a/src/geo/polygon.js
+++ b/src/geo/polygon.js
@@ -221,8 +221,62 @@
         return ret;
     };
 
-    PRO.miter = function() {
+    function slopeDiff(s1, s2) {
+        const n1 = s1.angle;//(s1.angle + 360) % 360;
+        const n2 = s2.angle;//(s2.angle + 360) % 360;
+        let diff = n2 - n1;
+        while (diff < -180) diff += 360;
+        while (diff > 180) diff -= 360;
+        return Math.abs(diff);
+    }
+
+    PRO.miter = function(debug) {
+        if (this.length < 3) return this;
+
         // todo - to eliminate path sharps in renders
+        const slo = [], pa = this.points, pln = pa.length, open = this.open;
+        let last;
+        for (let i=1; i<pln; i++) {
+            slo.push(pa[i-1].slopeTo(last = pa[i]));
+        }
+        if (!open) {
+            slo.push(last.slopeTo(pa[0]));
+        }
+
+        const ang = new Array(pln).fill(0);
+        let redo = false;
+        const aln = open ? pln - 1 : pln;
+        for (let i=1; i<aln; i++) {
+            ang[i] = slopeDiff(slo[i-1], slo[i]);
+            redo |= ang[i] < 90;
+        }
+        if (!open) {
+            // ang[pln-1] = slopeDiff(slo[pln-2], slo[pln-1]);
+            ang[0] = slopeDiff(slo[pln-1], slo[0]);
+            redo |= ang[pln-1] > 90;
+            redo |= ang[0] > 90;
+        }
+        if (redo) {
+            const newp = newPolygon();
+            // newp.debug = this.debug = true;
+            newp.open = open;
+            for (let i=0; i<pln; i++) {
+                const p = pa[(i+pln) % pln];
+                const d = ang[(i+pln) % pln];
+                if (d > 90) {
+                    const s = slo[(i+pln) % pln];
+                    const pp = pa[(i+pln-1) % pln];
+                    const ps = slo[(i+pln-1) % pln];
+                    newp.push(p.follow(p.slopeTo(pp), 0.005));
+                    newp.push(p.follow(s, 0.005));
+                } else {
+                    p.parent = newp;
+                    newp.push(p);
+                }
+            }
+            return newp;
+        }
+        return this;
     };
 
     PRO.createConvexHull = function(points) {
diff --git a/src/geo/slope.js b/src/geo/slope.js
index 93f747d1..8f6ee07f 100644
--- a/src/geo/slope.js
+++ b/src/geo/slope.js
@@ -91,7 +91,7 @@
     PRO.invert = function() {
         this.dx = -this.dx;
         this.dy = -this.dy;
-        this.angle = 360 - this.angle;
+        this.angle = 180 - this.angle;
         return this;
     };
 
diff --git a/src/kiri/render.js b/src/kiri/render.js
index a33f0435..8ab4082e 100644
--- a/src/kiri/render.js
+++ b/src/kiri/render.js
@@ -3,7 +3,7 @@
 "use strict";
 
 (function() {
-    const KIRI = self.kiri, BASE = self.base, POLY = BASE.polygons;
+    const KIRI = self.kiri, BASE = self.base, POLY = BASE.polygons, newPolygon = BASE.newPolygon;
 
     class Render {
         constructor() {
@@ -164,6 +164,14 @@
 
             polys.forEach(poly => {
                 const contour = [];
+                poly = poly.miter();
+                // if (poly.debug) {
+                //     const save = this.current;
+                //     this.setLayer('debug.acute', 0xff0000).addPoly(poly, {thin:true});
+                //     this.setLayer('debug.start', 0x00ff00).addPoly(newPolygon().centerRectangle(poly.first(),1,1), {thin:true});
+                //     this.setLayer('debug.end', 0x0000ff).addPoly(newPolygon().centerRectangle(poly.last(),0.8,0.8), {thin:true});
+                //     this.current = save;
+                // }
                 poly.points.forEach(p => {
                     contour.push(new THREE.Vector2(p.x, p.y));
                 });
diff --git a/src/license.js b/src/license.js
index f50162eb..395551a7 100644
--- a/src/license.js
+++ b/src/license.js
@@ -3,7 +3,7 @@
     let terms = {
         COPYRIGHT: "Copyright (C) Stewart Allen <sa@grid.space> - All Rights Reserved",
         LICENSE: "See the license.md file included with the source distribution",
-        VERSION: "2.3.D5"
+        VERSION: "2.3.D6"
     };
 
     if (typeof(module) === 'object') {
diff --git a/src/mode/fdm/prepare.js b/src/mode/fdm/prepare.js
index e4693e45..a4068106 100644
--- a/src/mode/fdm/prepare.js
+++ b/src/mode/fdm/prepare.js
@@ -484,7 +484,7 @@
                 lastOut = out;
             });
             if (lastOut.emit) {
-                pushPrint(lastOut.tool, current)
+                // pushPrint(lastOut.tool, current)
             } else {
                 moves.push(current);
             }