fix slicing of slabs (requires pocket bottom revisit)

src/kiri/mode/cam/cl-ops.js

@@ -14,7 +14,7 @@ const { MODES } = api.const;
 const { uc: UC } = api;
 const { alerts, conf } = api;
 const { current: LANG } = api.language;
-const { toInt, toFloat } = UC;
+const { toInt, toFloat, toFloatArray } = UC;
 
 const units = true;
 let seed = Date.now();

src/kiri/mode/cam/op-outline.js

@@ -15,6 +15,10 @@ class OpOutline extends CamOp {
     async slice(progress) {
         let { op, state } = this;
         let { shadow, tool, widget } = state;
+        let shadow_base = shadow.base;
+        if (!(shadow_base && shadow_base.length)) {
+            throw 'missing shadow base';
+        }
         let areas = POLY.flatten(POLY.expand(shadow.base, tool.fluteDiameter() / 2 - 0.001));
         let cutout = {
             areas: { [widget.id]: areas.map(p => p.toArray()) },