diff --git a/src/kiri-mode/cam/ops.js b/src/kiri-mode/cam/ops.js
index 5810d4d9..992ff651 100644
--- a/src/kiri-mode/cam/ops.js
+++ b/src/kiri-mode/cam/ops.js
@@ -957,7 +957,7 @@ class OpPocket extends CamOp {
     }
 
     slice(progress) {
-        const debug = true;
+        const debug = false;
         let { op, state } = this;
         let { tool, rate, down, plunge, expand, contour, smooth } = op;
         let { settings, widget, sliceAll, zMax, zTop, zThru, tabs, color } = state;
@@ -970,6 +970,23 @@ class OpPocket extends CamOp {
         let cutdir = process.camConventional;
         if (contour) {
             down = 0;
+            let topo = new CAM.Topo({
+                // onupdate: (update, msg) => {
+                onupdate: (index, total, msg) => {
+                    progress(index / total, msg);
+                },
+                ondone: (slices) => {
+                    this.sliceOut = slices;
+                    sliceAll.appendAll(slices);
+                },
+                contour: {
+                    tolerance: 0,
+                    inside: true,
+                    tool: tool,
+                    axis: "-"
+                },
+                state: state
+            });
         }
         updateToolDiams(toolDiam);
         if (tabs) {
diff --git a/src/kiri-mode/cam/topo.js b/src/kiri-mode/cam/topo.js
index 1167acb0..131b3798 100644
--- a/src/kiri-mode/cam/topo.js
+++ b/src/kiri-mode/cam/topo.js
@@ -55,7 +55,9 @@ class Topo {
             R2A = 180 / Math.PI,
             stepsx = Math.ceil(boundsX / resolution),
             stepsy = Math.ceil(boundsY / resolution),
-            topo = widget.topo = {
+            widtopo = widget.topo,
+            topoCache = widtopo && widtopo.resolution === resolution ? widtopo : undefined,
+            topo = widget.topo = topoCache || {
                 data: new Float32Array(stepsx * stepsy),
                 stepsx: stepsx,
                 stepsy: stepsy,
@@ -83,8 +85,8 @@ class Topo {
             debug_topo_shells = debug && true,
             time = Date.now;
 
-        if (tolerance == 0) {
-            console.log(`contour auto tolerance`,resolution.round(4));
+        if (tolerance === 0 && !topoCache) {
+            console.log(widget.id, 'topo auto tolerance', resolution.round(4));
         }
 
         this.tolerance = resolution;
@@ -193,7 +195,7 @@ class Topo {
 
         function raster(slices) {
             if (!topo.raster) {
-                // console.log({skipping_raster: widget.id});
+                console.log(widget.id, 'topo raster cached');
                 return;
             }
             topo.raster = false;
diff --git a/web/kiri/lang/en.js b/web/kiri/lang/en.js
index 984d38f3..79489063 100644
--- a/web/kiri/lang/en.js
+++ b/web/kiri/lang/en.js
@@ -516,7 +516,7 @@ self.kiri.lang['en-us'] = {
     cp_xpnd_s:      "expand",
     cp_xpnd_l:      ["grow selected area to","encompass corners"],
     cp_smoo_s:      "smooth",
-    cp_smoo_l:      ["clean up jagged edges caused by highly angled walls. can speedup pocketing for detailed geometries. recommend a value around 1"],
+    cp_smoo_l:      ["clean up jagged edges caused by angled walls. can speedup and improve pocketing for detailed geometries. recommend starting with values around 1"],
     cp_cont_s:      "contour",
     cp_cont_l:      ["ignore interior voids and features"],
     cp_outl_s:      "outline only",