diff --git a/src/kiri/app/api.js b/src/kiri/app/api.js
index 360775cd..49b5f11e 100644
--- a/src/kiri/app/api.js
+++ b/src/kiri/app/api.js
@@ -22,7 +22,7 @@ import { local } from './local.js';
 import { local as dataLocal } from '../../data/local.js';
 import { modal } from './modal.js';
 import { mode as modeModule, process as processModule } from './mode.js';
-import { newWidget } from '../core/widget.js';
+import { newWidget } from './widget.js';
 import { noop, ajax, o2js, js2o, utils } from '../core/utils.js';
 import { openFiles } from './files.js';
 import { platform } from './platform.js';
diff --git a/src/kiri/app/frame.js b/src/kiri/app/frame.js
index ee8ddc37..ca814ae3 100644
--- a/src/kiri/app/frame.js
+++ b/src/kiri/app/frame.js
@@ -25,7 +25,7 @@
 
 import { api } from './api.js';
 import { load } from '../../load/file.js';
-import { newWidget } from '../core/widget.js';
+import { newWidget } from './widget.js';
 import { VIEWS } from '../core/consts.js';
 import { widgets } from '../core/widgets.js';
 
diff --git a/src/kiri/app/groups.js b/src/kiri/app/groups.js
index 92434c69..fd189742 100644
--- a/src/kiri/app/groups.js
+++ b/src/kiri/app/groups.js
@@ -1,7 +1,7 @@
 /** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
 
 import { selection } from './selected.js';
-import { Widget } from '../core/widget.js';
+import { Widget } from './widget.js';
 
 /**
  * Merge selected widgets into a group.
diff --git a/src/kiri/app/image.js b/src/kiri/app/image.js
index 2867436d..97fda375 100644
--- a/src/kiri/app/image.js
+++ b/src/kiri/app/image.js
@@ -2,7 +2,7 @@
 
 import { $ } from '../../moto/webui.js';
 import { api } from './api.js';
-import { newWidget } from '../core/widget.js';
+import { newWidget } from './widget.js';
 import { platform } from './platform.js';
 import { settings } from './conf/manager.js';
 
diff --git a/src/kiri/app/platform.js b/src/kiri/app/platform.js
index 8523632c..3d8efc81 100644
--- a/src/kiri/app/platform.js
+++ b/src/kiri/app/platform.js
@@ -9,7 +9,7 @@ import { newBounds } from '../../geo/bounds.js';
 import { Packer } from './pack.js';
 import { space } from '../../moto/space.js';
 import { THREE } from '../../ext/three.js';
-import { Widget, newWidget } from '../core/widget.js';
+import { Widget, newWidget } from './widget.js';
 
 const V0 = new THREE.Vector3(0,0,0);
 
diff --git a/src/kiri/app/widget.js b/src/kiri/app/widget.js
new file mode 100644
index 00000000..b55dd548
--- /dev/null
+++ b/src/kiri/app/widget.js
@@ -0,0 +1,253 @@
+/** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
+
+import { Widget as WidgetCore } from '../core/widget.js';
+import { util } from '../../geo/base.js';
+import { avgc } from '../core/utils.js';
+
+const solid_opacity = 1.0;
+
+function catalog() { return self.kiri_catalog };
+function index() { return self.kiri_catalog.index }
+
+/**
+ * UI-enhanced Widget subclass for main thread
+ * Adds rendering, persistence, and visual state management
+ */
+class Widget extends WidgetCore {
+    /**
+     * Save widget geometry to catalog
+     */
+    saveToCatalog(filename, overwrite) {
+        if (!filename) {
+            filename = this.meta.file;
+        }
+        if (this.grouped && !overwrite) {
+            return this;
+        }
+        const widget = this;
+        const mark = Date.now();
+        const vertices = widget.getGeoVertices({ unroll: true }).slice();
+        widget.meta.file = filename;
+        widget.meta.save = mark;
+        catalog().putFile(filename, vertices, () => {
+            console.log("saved mesh ["+(vertices.length/3)+"] time ["+(Date.now()-mark)+"]");
+        });
+        return this;
+    }
+
+    /**
+     * Save widget state to index
+     */
+    saveState(ondone) {
+        if (!ondone) {
+            clearTimeout(this._save_timer);
+            this._save_timer = setTimeout(() => {
+                this._save_timer = undefined;
+                this.saveState(() => {});
+            }, 1500);
+            return;
+        }
+        const widget = this;
+        index().put('ws-save-'+this.id, {
+            geo: widget.getGeoVertices({ unroll: false }).slice(),
+            track: widget.track,
+            group: this.group.id,
+            meta: this.meta,
+            anno: this.annotations()
+        }, result => {
+            widget.meta.saved = Date.now();
+            if (ondone) ondone();
+        });
+    }
+
+    /**
+     * Set mesh material color
+     */
+    setColor(color, settings, save = true) {
+        if (settings) {
+            console.trace('legacy call with settings');
+        }
+        if (Array.isArray(color)) {
+            color = color[this.getExtruder() % color.length];
+        }
+        if (save) {
+            this.color = color;
+        }
+        let material = this.getMaterial();
+        material.color.set(this.meta.disabled ? avgc(0x888888, color, 3) : color);
+    }
+
+    /**
+     * Get current visual state
+     */
+    getVisualState() {
+        return {
+            edges: this.outline ? true : false,
+            wires: this.wire ? true : false,
+            opacity: this.getMaterial().opacity
+        };
+    }
+
+    /**
+     * Set visual state
+     */
+    setVisualState({ edges, wires, opacity}) {
+        this.cache.vizstate = this.getVisualState();
+        this.setEdges(edges ?? false);
+        this.setWireframe(wires ?? false);
+        this.setOpacity(opacity ?? 1);
+    }
+
+    /**
+     * Refresh visual state
+     */
+    refreshVisualState() {
+        this.setVisualState(this.getVisualState());
+    }
+
+    /**
+     * Restore previous visual state
+     */
+    restoreVisualState() {
+        if (this.cache.vizstate) {
+            this.setVisualState(this.cache.vizstate);
+        }
+    }
+
+    /**
+     * Set material opacity
+     */
+    setOpacity(value) {
+        const mat = this.getMaterial();
+        if (value <= 0.0) {
+            mat.transparent = solid_opacity < 1.0;
+            mat.opacity = solid_opacity;
+            mat.visible = false;
+        } else if (util.inRange(value, 0.0, solid_opacity)) {
+            mat.transparent = value < 1.0;
+            mat.opacity = value;
+            mat.visible = true;
+        }
+    }
+
+    /**
+     * Set edge rendering
+     */
+    setEdges(set) {
+        if (!(this.api && this.api.conf)) {
+            // missing api features in engine mode
+            return;
+        }
+        let mesh = this.mesh;
+        if (set && set.toggle) {
+            set = this.outline ? false : true;
+        }
+        if (this.outline) {
+            mesh.remove(this.outline);
+            this.outline = null;
+
+        }
+        if (set) {
+            let dark = this.api.space.is_dark();
+            let cam = this.api.mode.is_cam();
+            let color = dark ? 0x444444 : 0x888888;
+            let angle = this.api.conf.get().controller.edgeangle || 20;
+            let edges = new THREE.EdgesGeometry(mesh.geometry, angle);
+            let material = new THREE.LineBasicMaterial({ color });
+            this.outline = new THREE.LineSegments(edges, material);
+            this.outline.renderOrder = -20;
+            mesh.add(this.outline);
+        }
+    }
+
+    /**
+     * Set wireframe rendering
+     */
+    setWireframe(set, color, opacity) {
+        if (!(this.api && this.api.conf)) {
+            // missing api features in engine mode
+            return;
+        }
+        let mesh = this.mesh,
+            widget = this;
+        if (this.wire) {
+            this.setOpacity(solid_opacity);
+            mesh.remove(this.wire);
+            this.wire = null;
+        }
+        if (set) {
+            let dark = this.api.space.is_dark();
+            let mat = new THREE.MeshBasicMaterial({
+                wireframe: true,
+                color: dark ? 0xaaaaaa : 0,
+                opacity: 0.5,
+                transparent: true
+            })
+            let wire = widget.wire = new THREE.Mesh(mesh.geometry.shallowClone(), mat);
+            mesh.add(wire);
+        }
+        if (this.api.view.is_arrange()) {
+            this.setColor(this.color);
+        } else {
+            this.setColor(0x888888,undefined,false);
+        }
+        if (opacity !== undefined) {
+            widget.setOpacity(opacity);
+        }
+    }
+
+    /**
+     * Load widget from catalog
+     */
+    static loadFromCatalog(filename, ondone) {
+        catalog().getFile(filename, function(data) {
+            let widget = new Widget().loadVertices(data);
+            widget.meta.file = filename;
+            ondone(widget);
+        });
+    }
+
+    /**
+     * Load widget from saved state
+     */
+    static loadFromState(id, ondone, move) {
+        const Group = Widget.Groups;
+        index().get('ws-save-'+id, function(data) {
+            if (data) {
+                let vertices = data.geo || data,
+                    track = data.track || undefined,
+                    group = data.group || id,
+                    anno = data.anno || undefined,
+                    widget = new Widget(id, Group.forid(group)),
+                    meta = data.meta || widget.meta,
+                    ptr = widget.loadVertices(vertices);
+                widget.meta = meta;
+                widget.anno = anno || widget.anno;
+                // restore widget position if specified
+                if (move && track && track.pos) {
+                    widget.track = track;
+                    widget.move(track.pos.x, track.pos.y, track.pos.z, true);
+                }
+                ondone(ptr);
+            } else {
+                ondone(null);
+            }
+        });
+    }
+
+    /**
+     * Delete widget from saved state
+     */
+    static deleteFromState(id,ondone) {
+        index().remove('ws-save-'+id, ondone);
+    }
+}
+
+/**
+ * Factory function to create UI-enhanced widgets
+ */
+function newWidget(id, group) {
+    return new Widget(id, group);
+}
+
+export { Widget, newWidget };
diff --git a/src/kiri/app/workers.js b/src/kiri/app/workers.js
index e0a9871d..c508d10e 100644
--- a/src/kiri/app/workers.js
+++ b/src/kiri/app/workers.js
@@ -3,7 +3,7 @@
 import { api } from './api.js';
 import { noop } from '../core/utils.js';
 import { codec } from '../core/codec.js';
-import { Widget } from '../core/widget.js';
+import { Widget } from './widget.js';
 import { newPrint } from '../core/print.js';
 
 // this code runs in kiri's main loop
diff --git a/src/kiri/app/workspace.js b/src/kiri/app/workspace.js
index fd0f8806..92dd3d4b 100644
--- a/src/kiri/app/workspace.js
+++ b/src/kiri/app/workspace.js
@@ -9,7 +9,7 @@ import { selection } from './selected.js';
 import { settings } from './conf/manager.js';
 import { space as SPACE } from '../../moto/space.js';
 import { utils } from '../core/utils.js';
-import { Widget } from '../core/widget.js';
+import { Widget } from './widget.js';
 import { Index } from '../../data/index.js';
 
 const { o2js, js2o, ls2o, parseOpt } = utils;
diff --git a/src/kiri/core/widget.js b/src/kiri/core/widget.js
index 5206e58f..a1035977 100644
--- a/src/kiri/core/widget.js
+++ b/src/kiri/core/widget.js
@@ -1,7 +1,5 @@
 /** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
 
-import { base } from '../../geo/base.js';
-import { avgc } from './utils.js';
 import { util as mesh_util } from '../../mesh/util.js';
 import { tool as mesh_tool } from '../../mesh/tool.js';
 import { verticesToPoints } from '../../geo/points.js';
@@ -10,21 +8,13 @@ import { newPolygon } from '../../geo/polygon.js';
 import { polygons as POLY } from '../../geo/polygons.js';
 import { checkOverUnderOn, intersectPoints } from '../../geo/slicer.js';
 
-const { inRange, time } = base.util;
+const sharedArrayClass = self.SharedArrayBuffer || undefined;
+const hasSharedArrays = sharedArrayClass ? true : false;
 const solid_opacity = 1.0;
 const groups = [];
 
-const sharedArrayClass = self.SharedArrayBuffer || undefined;
-const hasSharedArrays = sharedArrayClass ? true : false;
-
 let nextId = 0;
 
-function newWidget(id,group) { return new Widget(id,group) }
-
-// todo: fix ui-only path thus this unorthodox binding vs importing api
-function catalog() { return self.kiri_catalog };
-function index() { return self.kiri_catalog.index }
-
 class Widget {
     constructor(id, group) {
         this.api = self.kiri_api;
@@ -98,46 +88,6 @@ class Widget {
         this.support = false;
     }
 
-    saveToCatalog(filename, overwrite) {
-        if (!filename) {
-            filename = this.meta.file;
-        }
-        if (this.grouped && !overwrite) {
-            return this;
-        }
-        const widget = this;
-        const mark = time();
-        const vertices = widget.getGeoVertices({ unroll: true }).slice();
-        widget.meta.file = filename;
-        widget.meta.save = mark;
-        catalog().putFile(filename, vertices, () => {
-            console.log("saved mesh ["+(vertices.length/3)+"] time ["+(time()-mark)+"]");
-        });
-        return this;
-    }
-
-    saveState(ondone) {
-        if (!ondone) {
-            clearTimeout(this._save_timer);
-            this._save_timer = setTimeout(() => {
-                this._save_timer = undefined;
-                this.saveState(() => {});
-            }, 1500);
-            return;
-        }
-        const widget = this;
-        index().put('ws-save-'+this.id, {
-            geo: widget.getGeoVertices({ unroll: false }).slice(),
-            track: widget.track,
-            group: this.group.id,
-            meta: this.meta,
-            anno: this.annotations()
-        }, result => {
-            widget.meta.saved = time();
-            if (ondone) ondone();
-        });
-    }
-
     annotations() {
         let o = Object.clone(this.anno);
         if (o.support) {
@@ -311,23 +261,6 @@ class Widget {
         this.slices = null;
     }
 
-    /**
-     * @param {number} color
-     */
-    setColor(color, settings, save = true) {
-        if (settings) {
-            console.trace('legacy call with settings');
-        }
-        if (Array.isArray(color)) {
-            color = color[this.getExtruder() % color.length];
-        }
-        if (save) {
-            this.color = color;
-        }
-        let material = this.getMaterial();
-        material.color.set(this.meta.disabled ? avgc(0x888888, color, 3) : color);
-    }
-
     getColor() {
         return this.color;
     }
@@ -362,47 +295,6 @@ class Widget {
         }
     }
 
-    getVisualState() {
-        return {
-            edges: this.outline ? true : false,
-            wires: this.wire ? true : false,
-            opacity: this.getMaterial().opacity
-        };
-    }
-
-    setVisualState({ edges, wires, opacity}) {
-        this.cache.vizstate = this.getVisualState();
-        this.setEdges(edges ?? false);
-        this.setWireframe(wires ?? false);
-        this.setOpacity(opacity ?? 1);
-    }
-
-    refreshVisualState() {
-        this.setVisualState(this.getVisualState());
-    }
-
-    restoreVisualState() {
-        if (this.cache.vizstate) {
-            this.setVisualState(this.cache.vizstate);
-        }
-    }
-
-    /**
-     * @param {number} value
-     */
-    setOpacity(value) {
-        const mesh = this.mesh;
-        const mat = this.getMaterial();
-        if (value <= 0.0) {
-            mat.transparent = solid_opacity < 1.0;
-            mat.opacity = solid_opacity;
-            mat.visible = false;
-        } else if (inRange(value, 0.0, solid_opacity)) {
-            mat.transparent = value < 1.0;
-            mat.opacity = value;
-            mat.visible = true;
-        }
-    }
 
     toggleVisibility(bool) {
         const mat = this.getMaterial();
@@ -574,10 +466,10 @@ class Widget {
         let mesh = this.mesh,
             scale = this.track.scale;
         this.bounds = null;
-        this.setWireframe(false);
+        if (this.setWireframe) this.setWireframe(false);
         this.clearSlices();
         mesh.geometry.applyMatrix4(new THREE.Matrix4().makeScale(x, y, z));
-        if (this.outline) {
+        if (this.outline && this.setEdges) {
             this.setEdges(true);
         }
         scale.x *= (x || 1.0);
@@ -593,7 +485,7 @@ class Widget {
         if (center) {
             this.center(false);
         }
-        if (this.outline) {
+        if (this.outline && this.setEdges) {
             this.setEdges(true);
         }
         if ((x || y || z) && this.api && this.api.event) {
@@ -604,7 +496,7 @@ class Widget {
     _rotate(x, y, z, temp) {
         if (!temp) {
             this.bounds = null;
-            this.setWireframe(false);
+            if (this.setWireframe) this.setWireframe(false);
             this.clearSlices();
         }
         let m4 = new THREE.Matrix4();
@@ -633,7 +525,7 @@ class Widget {
         this.roto = [];
         this.center();
         this.setModified();
-        this.refreshVisualState();
+        if (this.refreshVisualState) this.refreshVisualState();
     }
 
     mirror() {
@@ -648,7 +540,7 @@ class Widget {
 
     _mirror() {
         this.clearSlices();
-        this.setWireframe(false);
+        if (this.setWireframe) this.setWireframe(false);
         let geo = this.mesh.geometry, ot = this.track;
         let pos = geo.attributes.position;
         let arr = pos.array;
@@ -782,65 +674,6 @@ class Widget {
         return Date.now() - mark;
     }
 
-    setEdges(set) {
-        if (!(this.api && this.api.conf)) {
-            // missing api features in engine mode
-            return;
-        }
-        let mesh = this.mesh;
-        if (set && set.toggle) {
-            set = this.outline ? false : true;
-        }
-        if (this.outline) {
-            mesh.remove(this.outline);
-            this.outline = null;
-
-        }
-        if (set) {
-            let dark = this.api.space.is_dark();
-            let cam = this.api.mode.is_cam();
-            let color = dark ? 0x444444 : 0x888888;
-            let angle = this.api.conf.get().controller.edgeangle || 20;
-            let edges = new THREE.EdgesGeometry(mesh.geometry, angle);
-            let material = new THREE.LineBasicMaterial({ color });
-            this.outline = new THREE.LineSegments(edges, material);
-            this.outline.renderOrder = -20;
-            mesh.add(this.outline);
-        }
-    }
-
-    setWireframe(set, color, opacity) {
-        if (!(this.api && this.api.conf)) {
-            // missing api features in engine mode
-            return;
-        }
-        let mesh = this.mesh,
-            widget = this;
-        if (this.wire) {
-            this.setOpacity(solid_opacity);
-            mesh.remove(this.wire);
-            this.wire = null;
-        }
-        if (set) {
-            let dark = this.api.space.is_dark();
-            let mat = new THREE.MeshBasicMaterial({
-                wireframe: true,
-                color: dark ? 0xaaaaaa : 0,
-                opacity: 0.5,
-                transparent: true
-            })
-            let wire = widget.wire = new THREE.Mesh(mesh.geometry.shallowClone(), mat);
-            mesh.add(wire);
-        }
-        if (this.api.view.is_arrange()) {
-            this.setColor(this.color);
-        } else {
-            this.setColor(0x888888,undefined,false);
-        }
-        if (opacity !== undefined) {
-            widget.setOpacity(opacity);
-        }
-    }
 
     show() {
         this.mesh.visible = true;
@@ -1076,40 +909,8 @@ const Group = Widget.Groups = {
     }
 };
 
-Widget.loadFromCatalog = function(filename, ondone) {
-    catalog().getFile(filename, function(data) {
-        let widget = newWidget().loadVertices(data);
-        widget.meta.file = filename;
-        ondone(widget);
-    });
-};
-
-Widget.loadFromState = function(id, ondone, move) {
-    index().get('ws-save-'+id, function(data) {
-        if (data) {
-            let vertices = data.geo || data,
-                track = data.track || undefined,
-                group = data.group || id,
-                anno = data.anno || undefined,
-                widget = newWidget(id, Group.forid(group)),
-                meta = data.meta || widget.meta,
-                ptr = widget.loadVertices(vertices);
-            widget.meta = meta;
-            widget.anno = anno || widget.anno;
-            // restore widget position if specified
-            if (move && track && track.pos) {
-                widget.track = track;
-                widget.move(track.pos.x, track.pos.y, track.pos.z, true);
-            }
-            ondone(ptr);
-        } else {
-            ondone(null);
-        }
-    });
-};
-
-Widget.deleteFromState = function(id,ondone) {
-    index().remove('ws-save-'+id, ondone);
-};
+function newWidget(id,group) {
+    return new Widget(id,group);
+}
 
 export { Widget, newWidget };
diff --git a/src/kiri/core/widgets.js b/src/kiri/core/widgets.js
index 5db6f325..39d621ee 100644
--- a/src/kiri/core/widgets.js
+++ b/src/kiri/core/widgets.js
@@ -3,7 +3,7 @@
 import { $ } from '../../moto/webui.js';
 import { api } from '../app/api.js';
 import { load } from '../../load/file.js';
-import { Widget, newWidget } from './widget.js';
+import { Widget, newWidget } from '../app/widget.js';
 
 let WIDGETS = [];
 
diff --git a/src/kiri/mode/cam/init-ui.js b/src/kiri/mode/cam/init-ui.js
index 55fdd744..706cb456 100644
--- a/src/kiri/mode/cam/init-ui.js
+++ b/src/kiri/mode/cam/init-ui.js
@@ -16,7 +16,7 @@ import { holeSelOn, selectHolesDone, clearHolesRec } from './cl-hole.js';
 import { surfaceOn, surfaceDone } from './cl-surface.js';
 import { helicalOn, helicalDone } from './cl-helical.js';
 import { originSelectDone } from './cl-origin.js';
-import { Widget, newWidget } from '../../core/widget.js';
+import { Widget, newWidget } from '../../app/widget.js';
 import { space } from '../../../moto/space.js';
 import { recreateTabs } from './cl-tab.js';
 
diff --git a/src/kiri/mode/fdm/init-ui.js b/src/kiri/mode/fdm/init-ui.js
index d0da4218..f7e4d0ff 100644
--- a/src/kiri/mode/fdm/init-ui.js
+++ b/src/kiri/mode/fdm/init-ui.js
@@ -8,7 +8,7 @@ import { client } from '../../app/workers.js';
 import { addbox, delbox, getlastbox } from '../../core/boxes.js';
 import { Layers } from '../../app/layers.js';
 import { Stack } from '../../app/stack.js';
-import { Widget, newWidget } from '../../core/widget.js';
+import { Widget, newWidget } from '../../app/widget.js';
 import { space } from '../../../moto/space.js';
 
 const { Matrix4, Vector3, BufferAttribute, BufferGeometryUtils, Raycaster, Euler } = THREE;
diff --git a/src/kiri/run/engine.js b/src/kiri/run/engine.js
index eb5aa5a5..deb29d57 100644
--- a/src/kiri/run/engine.js
+++ b/src/kiri/run/engine.js
@@ -7,7 +7,7 @@ import { api } from '../app/api.js';
 import { conf } from '../app/conf/defaults.js';
 import { client } from '../app/workers.js';
 import { load } from '../../load/file.js';
-import { newWidget } from '../core/widget.js';
+import { newWidget } from '../app/widget.js';
 
 class Engine {
     constructor({ workURL, poolURL } = {}) {