diff --git a/src/kiri/core/platform.js b/src/kiri/core/platform.js
index 194d1f2a..48c90282 100644
--- a/src/kiri/core/platform.js
+++ b/src/kiri/core/platform.js
@@ -163,19 +163,19 @@ function platformUpdateTopZ() {
             const wzmax = bounds.max.z;
             const zdelta = process.camZOffset || 0;
             switch (process.camZAnchor) {
-               case 'top':
-                   widget.setTopZ(stock.z - zdelta);
-                   break;
-               case 'middle':
-                   if (widget.isIndexed) {
-                       widget.setTopZ(zdelta);
-                   } else {
-                       widget.setTopZ(stock.z - (stock.z - wzmax) / 2 + zdelta);
-                   }
-                   break;
-               case 'bottom':
-                   widget.setTopZ(wzmax + zdelta);
-                   break;
+                case 'top':
+                    widget.setTopZ(stock.z - zdelta, true);
+                    break;
+                case 'middle':
+                    if (widget.isIndexed) {
+                        widget.setTopZ(zdelta, true);
+                    } else {
+                        widget.setTopZ(stock.z - (stock.z - wzmax) / 2 + zdelta, true);
+                    }
+                    break;
+                case 'bottom':
+                    widget.setTopZ(wzmax + zdelta, true);
+                    break;
             }
         } else {
             widget.setTopZ(0);
diff --git a/src/kiri/core/widget.js b/src/kiri/core/widget.js
index 47222eb7..85b16879 100644
--- a/src/kiri/core/widget.js
+++ b/src/kiri/core/widget.js
@@ -473,10 +473,12 @@ class Widget {
 
     /**
      * moves top of widget to given Z
+     * only non-zero in CAM mode
      *
      * @param {number} z position
+     * @param {boolean} cam mode
      */
-    setTopZ(z) {
+    setTopZ(z, cam) {
         let mesh = this.mesh,
             track = this.track,
             mbb = mesh.getBoundingBox(),
@@ -488,7 +490,7 @@ class Widget {
             track.top = mbz;
         }
         // difference between top of stock/bounds and top of widget (cam mode)
-        track.tzoff = mbz - z;
+        track.tzoff = cam ? mbz - z : 0;
         this._updateMeshPosition();
     }
 
@@ -503,8 +505,7 @@ class Widget {
     }
 
     _move(x, y, z, abs) {
-        let mesh = this.mesh,
-            mat = this.getMaterial(),
+        let mat = this.getMaterial(),
             pos = this.track.pos;
         // do not allow moves in pure slice view
         if (!mat.visible) return;
@@ -528,13 +529,10 @@ class Widget {
             track = this.track,
             tzoff = track.tzoff,
             top = track.top,
-            tz = tzoff !== top ? -tzoff : 0,
+            tz = -tzoff,
             { x, y, z } = track.pos;
         if (track.indexed) {
             let rad = track.indexRad;
-            let ln = track.box.d / 2;
-            let dx = Math.sin(rad) * ln;
-            let dy = ln - Math.cos(rad) * ln;
             this.mesh.rotation.x = -rad;
             z = top;
         } else {