diff --git a/src/kiri-mode/fdm/slice.js b/src/kiri-mode/fdm/slice.js
index 2094da83..b1f99d05 100644
--- a/src/kiri-mode/fdm/slice.js
+++ b/src/kiri-mode/fdm/slice.js
@@ -572,6 +572,9 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
         }
 
         // calculations only relevant when solid layers are used
+        // layer boolean diffs need to be computed to find flat areas to fill
+        // and overhangs that need to be supported. these are stored in flats
+        // and bridges, projected up/down, and merged into an array of solids
         if (solidLayers && !vaseMode && !isSynth) {
             profileStart("delta");
             forSlices(0.2, 0.34, slice => {
@@ -609,8 +612,9 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
             profileEnd();
         }
 
+        // for "real" objects, fill the remaining voids with sparse fill
+        // sparse layers only present when non-vase mose and sparse % > 0
         if (!isSynth && !vaseMode) {
-            // sparse layers only present when non-vase mose and sparse % > 0
             let lastType;
             // disabled until memory issue tracked down
             let promises = false && isConcurrent ? [] : undefined;
diff --git a/src/kiri/slice.js b/src/kiri/slice.js
index d46ec09a..5ce1d343 100644
--- a/src/kiri/slice.js
+++ b/src/kiri/slice.js
@@ -174,16 +174,15 @@ class Slice {
         return min;
     };
 
-    xray(dash = 3) {
-        // console.log('xray', this);
-        this.output().setLayer(`xp`, 0x888800).addPolys(this.topPolys());
-        this.lines.forEach((line, i) => {
-            const group = i % dash;
-            const color = [ 0xff0000, 0x00ff00, 0x0000ff, 0xffff00, 0xff00ff ][group];
-            this.output().setLayer(`xl-${group}`, color).addLine(line.p1, line.p2);
-        });
-    }
-
+    // xray(dash = 3) {
+    //     // console.log('xray', this);
+    //     this.output().setLayer(`xp`, 0x888800).addPolys(this.topPolys());
+    //     this.lines.forEach((line, i) => {
+    //         const group = i % dash;
+    //         const color = [ 0xff0000, 0x00ff00, 0x0000ff, 0xffff00, 0xff00ff ][group];
+    //         this.output().setLayer(`xl-${group}`, color).addLine(line.p1, line.p2);
+    //     });
+    // }
 }
 
 /**
diff --git a/src/kiri/stack.js b/src/kiri/stack.js
index c1862907..9b7556fc 100644
--- a/src/kiri/stack.js
+++ b/src/kiri/stack.js
@@ -262,8 +262,6 @@ function createPhongMaterial(color, flat) {
 
 function createLambertMaterial(color, flat) {
     return new THREE.MeshLambertMaterial({
-        // shininess,
-        // specular,
         transparent: color.opacity != 1,
         opacity: color.opacity || 1,
         color: color.face,