diff --git a/package.json b/package.json
index 2e0dd3ea..a71a66c1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "grid-apps",
-    "version": "2.4.11D",
+    "version": "2.4.12D",
     "description": "grid.space 3d slice & modeling tools",
     "author": "Stewart Allen <sa@grid.space>",
     "license": "MIT",
diff --git a/src/kiri.js b/src/kiri.js
index 6e81157b..fb54dd5f 100644
--- a/src/kiri.js
+++ b/src/kiri.js
@@ -6,7 +6,7 @@
 
     if (!self.kiri) {
         self.kiri = {
-            beta: 2411,
+            beta: 2412,
             driver: {}, // driver modules
             loader: []  // module loading: array of functions
         };
diff --git a/src/license.js b/src/license.js
index abc43a8d..68889d4c 100644
--- a/src/license.js
+++ b/src/license.js
@@ -3,7 +3,7 @@
     let terms = {
         COPYRIGHT: "Copyright (C) Stewart Allen <sa@grid.space> - All Rights Reserved",
         LICENSE: "See the license.md file included with the source distribution",
-        VERSION: "2.4.D11"
+        VERSION: "2.4.D12"
     };
 
     if (typeof(module) === 'object') {
diff --git a/src/mode/cam/slice.js b/src/mode/cam/slice.js
index 093523f7..c295b6b8 100644
--- a/src/mode/cam/slice.js
+++ b/src/mode/cam/slice.js
@@ -561,9 +561,15 @@
         }
 
         // add shadow perimeter to terrain to catch outside moves off part
-        let shadowOff = POLY.offset(shadowTop.tops, minToolDiam / 2);
+        let tabpoly = tabs ? tabs.map(tab => tab.poly) : [];
+        let allpoly = POLY.union([...shadowTop.tops, ...tabpoly], 0, true);
+        let shadowOff = POLY.offset(allpoly, [minToolDiam/2,maxToolDiam/2], { count: 2, flat: true });
         terrain.forEach(level => level.tops.appendAll(shadowOff));
 
+        // let dslice = KIRI.newSlice(-1);
+        // dslice.output().setLayer("shadowOff", { line: 0xff0000 }).addPolys(shadowOff);
+        // sliceAll.push(dslice);
+
         widget.terrain = terrain;
         widget.minToolDiam = minToolDiam;
         widget.maxToolDiam = maxToolDiam;