diff --git a/src/kiri-mode/cam/prepare.js b/src/kiri-mode/cam/prepare.js
index e3ef4fd2..b0fdca69 100644
--- a/src/kiri-mode/cam/prepare.js
+++ b/src/kiri-mode/cam/prepare.js
@@ -346,7 +346,7 @@ function prepEach(widget, settings, print, firstPoint, update) {
                 // new pos for plunge calc
                 deltaXY = 0;
             }
-        } else if (isMove && currentOp.type === 'lathe') {
+        } else if (isMove && ['lathe','contour'].contains(currentOp.type)) {
             if (point.z > lastPoint.z) {
                 layerPush(lastPoint.clone().setZ(point.z), 0, 0, tool.getNumber());
             } else if (point.z < lastPoint.z) {
diff --git a/src/kiri-mode/cam/slice.js b/src/kiri-mode/cam/slice.js
index ae8bf752..953c33c1 100644
--- a/src/kiri-mode/cam/slice.js
+++ b/src/kiri-mode/cam/slice.js
@@ -239,14 +239,14 @@ CAM.slice = async function(settings, widget, onupdate, ondone) {
         });
         tracker.rotation = isIndexed ? axisRotation : 0;
         // setup new state when indexing the workspace
-        if (true && op.op.type === "index") {
+        if (op.op.type === "index") {
+            widget.topo = undefined;
             // let points = base.verticesToPoints();
             state.slicer = new kiri.cam_slicer(widget);
             shadows = {};
             await new CAM.OPS.shadow(state, { type: "shadow", silent: true }).slice(progress => {
                 // console.log('reshadow', progress.round(3));
             });
-            widget.topo = undefined;
         }
         camOps.push(op);
         opSum += weight;
diff --git a/src/kiri-mode/cam/topo.js b/src/kiri-mode/cam/topo.js
index b87a52fd..b5d9c44a 100644
--- a/src/kiri-mode/cam/topo.js
+++ b/src/kiri-mode/cam/topo.js
@@ -87,7 +87,7 @@ class Topo {
             clipTo = inside ? shadow : POLY.expand(shadow, toolDiameter/2 + resolution * 3),
             partOff = inside ? 0 : toolDiameter / 2 + resolution,
             gridDelta = Math.floor(partOff / resolution),
-            debug = true,
+            debug = false,
             debug_clips = debug && true,
             debug_topo = debug && true,
             debug_topo_lines = debug && true,
@@ -205,7 +205,7 @@ class Topo {
         const { box } = params;
         const { worker, minions } = kiri;
 
-        const vertices = widget.getGeoVertices().toShared();
+        const vertices = widget.getGeoVertices({ unroll: true, translate: true }).toShared();
         const range = { min: Infinity, max: -Infinity };
 
         // swap XZ in shared array
@@ -449,7 +449,7 @@ class Probe {
                 xl = sx - 1,
                 yl = sy - 1;
 
-            let gv, i = 0, mz = -1;
+            let gv, i = 0, mz = -Infinity;
 
             while (i < profile.length) {
                 // tool profile point x, y, and z offsets
@@ -467,7 +467,7 @@ class Probe {
                 mz = Math.max(tz + gv, mz);
             }
 
-            return Math.max(mz, 0);
+            return Math.max(mz, zMin);
         }
 
         // export z probe function
@@ -777,7 +777,7 @@ function raster_slice(inputs) {
     // rasterize one x slice
     for (y = minY; y < maxY && gridy < stepsY; y += resolution) {
         gridi = gridx * stepsY + gridy;
-        gridv = data[gridi] || 0;
+        gridv = data[gridi] || zMin;
         // strategy using raw lines (faster slice, but more lines)
         for (i=0, il=points.length; i<il; i += 2) {
             const p1 = points[i], p2 = points[i+1];
diff --git a/src/kiri-mode/cam/topo4.js b/src/kiri-mode/cam/topo4.js
index 610c63d8..eefac473 100644
--- a/src/kiri-mode/cam/topo4.js
+++ b/src/kiri-mode/cam/topo4.js
@@ -279,6 +279,10 @@ class Topo4 {
                         mz = Math.max(mz, lz);
                     }
                 }
+                if (mz === -Infinity && xo === 0 && yo === 0) {
+                    // tool tip is off the model
+                    break;
+                }
             }
             if (mz === -Infinity) {
                 mz = Math.max(lz, 0);