diff --git a/src/kiri/print.js b/src/kiri/print.js
index 613dbdcc..abeb85db 100644
--- a/src/kiri/print.js
+++ b/src/kiri/print.js
@@ -316,13 +316,24 @@
                     // used for renderMoves client side. can drop non-essential
                     // data to speed up worker -> browser transfer. perhaps a
                     // more compact encoding (arrays, etc)
-                    newlayer.push({
-                        emit: out.emit,
-                        speed: out.speed * 60,
-                        retract: out.retract,
-                        point: {x: out.point.x, y: out.point.y, z: out.point.z},
-                        tool: out.tool
-                    });
+                    let push = { };
+                    if (out.emit !== undefined) push.emit = out.emit;
+                    if (out.speed !== undefined) push.speed = out.speed * 60;
+                    if (out.retract !== undefined) push.retract = out.retract;
+                    if (out.point !== undefined) push.point = {
+                        x: out.point.x, y: out.point.y, z: out.point.z
+                    };
+                    if (out.tool !== undefined) push.tool = out.tool;
+                    if (layerout.thick !== undefined) push.thick = layerout.thick;
+                    newlayer.push(push);
+                    // newlayer.push({
+                    //     emit: out.emit,
+                    //     speed: out.speed * 60,
+                    //     retract: out.retract,
+                    //     point: {x: out.point.x, y: out.point.y, z: out.point.z},
+                    //     tool: out.tool,
+                    //     thick: layerout.thick
+                    // });
                 }
             });
         });
diff --git a/src/kiri/slicer.js b/src/kiri/slicer.js
index de012f8c..f7f6a0b8 100644
--- a/src/kiri/slicer.js
+++ b/src/kiri/slicer.js
@@ -109,6 +109,7 @@
             zHeights = [],      // heights for zIndexes in adaptive mode
             zIndexes = [],      // auto-detected z slicing offsets (laser/cam)
             zOrdered = [],      // ordered list of Z indexes
+            zThick = [],        // ordered list of Z slice thickness (laser)
             zList = {},         // map count of z index points for adaptive slicing
             zFlat = {},         // map area of z index flat areas (cam)
             zLines = {},        // map count of z index lines
@@ -255,6 +256,7 @@
             }
             for (i = 0; i < zl.length - 1; i++) {
                 zIndexes.push((zl[i] + zl[i+1]) / 2);
+                zThick.push(zl[i+1] - zl[i]);
             }
         } else if (isCam) {
             // re-divide slice height so that top and
@@ -346,7 +348,7 @@
                 zIndexes[i] += isCam ? 0.001 : -0.001;
             }
             // slice next layer and add to slices[] array
-            let slice = sliceZ(zIndexes[i], zHeights[i], onFlat, onLine);
+            let slice = sliceZ(zIndexes[i], zHeights[i], onFlat, onLine, zThick[i]);
             // override z in cam in case it was moved for a flat or line
             if (isCam && slice) {
                 slice.z = zHeights[i];
@@ -451,7 +453,7 @@
          * @param {number} z
          * @param {number} [height] optional real height (fdm)
          */
-        function sliceZ(z, height, onflat, online) {
+        function sliceZ(z, height, onflat, online, thick) {
             let phash = {},
                 lines = [],
                 slice = newSlice(z, options.view ? options.view.newGroup() : null),
@@ -507,6 +509,7 @@
             slice.height = height;
             slice.index = slices.length;
             slice.lines = removeDuplicateLines(lines);
+            slice.thick = thick;
 
             // for topo slices, we just need the raw lines
             if (!topoMode && !simpleMode) {
diff --git a/src/mode/laser/driver.js b/src/mode/laser/driver.js
index 39eda463..7dcbea22 100644
--- a/src/mode/laser/driver.js
+++ b/src/mode/laser/driver.js
@@ -65,6 +65,8 @@
         let grouped = process.outputLaserGroup;
         let group = [];
 
+        group.thick = slice.thick;
+
         function laserOut(poly, group) {
             if (!poly) {
                 return;
@@ -84,6 +86,7 @@
             if (!grouped) {
                 groups.push(group);
                 group = [];
+                group.thick = slice.thick;
             }
         });
 
@@ -210,7 +213,6 @@
      *
      */
     function exportElements(print, onpre, onpoly, onpost, onpoint) {
-
         let process = print.settings.process,
             output = print.output,
             last,
@@ -266,8 +268,10 @@
         onpre(min, max, process.outputLaserPower, process.outputLaserSpeed);
 
         output.forEach(function(layer) {
+            let thick = 0;
             let color = 0;
             layer.forEach(function(out) {
+                thick = out.thick;
                 point = out.point;
                 if (out.emit) {
                     color = out.emit;
@@ -276,13 +280,13 @@
                     }
                     poly.push(onpoint(point));
                 } else if (poly.length > 0) {
-                    onpoly(poly, color);
+                    onpoly(poly, color, thick);
                     poly = [];
                 }
                 last = point;
             });
             if (poly.length > 0) {
-                onpoly(poly, color);
+                onpoly(poly, color, thick);
                 poly = [];
             }
         });
@@ -375,9 +379,12 @@
                 lines.push('<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">');
                 lines.push(`<svg width="${width}mm" height="${height}mm" viewBox="0 0 ${width} ${height}" xmlns="http://www.w3.org/2000/svg" version="1.1">`);
             },
-            function(poly, color) {
+            function(poly, color, thick) {
                 let cout = colors[((color-1) % colors.length)];
-                lines.push(`<polyline z="${z}" points="${poly.join(' ')}" fill="none" stroke="${cout}" stroke-width="0.1mm" />`);
+                let def = ["polyline"];
+                if (z != undefined) def.push(`z="${z}"`);
+                if (thick != undefined) def.push(`h="${thick}"`);
+                lines.push(`<${def.join(' ')} points="${poly.join(' ')}" fill="none" stroke="${cout}" stroke-width="0.1mm" />`);
             },
             function() {
                 lines.push("</svg>");