diff --git a/src/kiri/print.js b/src/kiri/print.js
index ea63a35b..3ba0adc5 100644
--- a/src/kiri/print.js
+++ b/src/kiri/print.js
@@ -113,11 +113,12 @@
             seq = [],
             abs = true,
             move = false,
+            defh = 0,
             height = 0,
             factor = 1,
             tool = 0,
             E0G0 = false,
-            G0 = function() {
+            moving = function() {
                 move = true;
                 if (seq.length > 0) {
                     output.push(seq);
@@ -146,6 +147,10 @@
             };
 
         lines.forEach(function(line) {
+            if (line.indexOf('- LAYER ') > 0) {
+                const hd = line.replace('(','').replace(')','').split(' ');
+                defh = parseFloat(hd[4]);
+            }
             line = line.split(";")[0].split(" ");
             let cmd = line.shift();
             if (cmd.charAt(0) === 'T') {
@@ -172,11 +177,14 @@
                     abs = false;
                     break;
                 case 'G0':
-                    G0();
+                    moving();
                 case 'G1':
                     line.forEach(function(tok) {
                         pos[tok.charAt(0)] = parseFloat(tok.substring(1));
                     });
+                    if (seq.Z === undefined && pos.Z) {
+                        seq.Z = pos.Z;
+                    }
                     if (pos.X) bounds.min.x = Math.min(bounds.min.x, pos.X * factor);
                     if (pos.X) bounds.max.x = Math.max(bounds.max.x, pos.X * factor);
                     if (pos.Y) bounds.min.y = Math.min(bounds.min.y, pos.Y * factor);
@@ -185,10 +193,10 @@
                     if (pos.Z) bounds.max.z = Math.max(bounds.max.z, pos.Z * factor);
                     if (pos.E) E0G0 = true;
                     if (E0G0 && pos.E === 0.0) {
-                        if (LZ != pos.Z) G0();
+                        if (LZ != pos.Z) moving();
                         else move = true;
                         if (move && pos.Z > LMZ) {
-                            height = seq.height = pos.Z - LMZ;
+                            height = seq.height = defh || pos.Z - LMZ;
                         }
                     }
                     addOutput(
@@ -206,13 +214,15 @@
                 case 'M6':
                     break;
             }
+            if (move) {
+                LMZ = Math.max(pos.Z, LMZ);
+            }
             move = false;
             pos.E = 0.0;
             LZ = pos.Z;
-            LMZ = Math.max(LZ, LMZ);
         });
 
-        G0();
+        moving();
 
         scope.imported = gcode;
         scope.lines = lines.length;
diff --git a/src/mode/fdm/prepare.js b/src/mode/fdm/prepare.js
index 9513a426..557d1725 100644
--- a/src/mode/fdm/prepare.js
+++ b/src/mode/fdm/prepare.js
@@ -381,6 +381,22 @@
         return print.render;
     };
 
+    class Counter {
+        constructor() {
+            this.map = {};
+            this.total = 0;
+        }
+        put(key) {
+            const map = this.map;
+            const kp = key || 'bad';
+            map[kp] = (map[kp] || 0) + 1;
+            this.total++;
+        }
+        get() {
+            return { map: this.map, total: this.total };
+        }
+    }
+
     FDM.prepareRender = function(levels, update, options) {
         const opts = options || {};
         const tools = opts.tools || {};
@@ -390,11 +406,13 @@
         const printColor = opts.print >= 0 ? opts.print : 0x777700;
         const layers = [];
         const maxspd = levels.map(level => {
-            return level.map(o => o.speed || 0).reduce((a, v) => Math.max(a,v));
-        }).reduce((a, v) => Math.max(a, v));
+            return level.map(o => o.emit || true ? o.speed || 0 : 0).reduce((a, v) => Math.max(a,v));
+        }).reduce((a, v) => Math.max(a, v)) + 1;
 
         let lastOut = null;
         let current = null;
+        const cn_len = new Counter();
+        const cn_col = new Counter();
 
         levels.forEach((level, index) => {
             const prints = {};
@@ -458,17 +476,18 @@
                 .setLayer('move', moveColor, true)
                 .addPolys(moves, { thin: true, z: opts.z });
             Object.values(prints).forEach(array => {
-                array.forEach(poly => { output
+                array.forEach(poly => { if (poly.length > 1) output
                     .setLayer(opts.action || 'print', printColor)
                     .addPolys([ poly ], thin ? { thin, z: opts.z } : {
                         offset: array.width, height, z: opts.z,
                         color: { face: poly.color, line: poly.color }
-                    })
-                })
+                    })// & cn_len.put(poly.length) & cn_col.put(poly.color) & console.log(poly.points)
+                });
             });
 
             update(index / levels.length);
         });
+        // console.log(cn_len.get(), cn_col.get());
 
         return layers;
     }