diff --git a/notes.md b/notes.md
index 6cd11088..5e6e8912 100644
--- a/notes.md
+++ b/notes.md
@@ -119,10 +119,10 @@
 # Mesh:Tool
 
 * add undo/redo
+* click to repair normals based on a known good (selected) face
 * send to Kiri:Moto workspace (or update model vertices in place)
 * better z snap using just vertexes from face intersected
 * add section view. local clip. raycast skip points above plane
-* add isolate op = separate bodies
 * add decimate op = face reduction
 * add flatten/crush op: for z bottoms (or surfaces?)
 * allow setting model/group origin for scale/rotate
diff --git a/release.md b/release.md
index 7cbad9e4..f79be8e8 100644
--- a/release.md
+++ b/release.md
@@ -2,6 +2,10 @@
 
 Full docs @ https://docs.grid.space/projects/kiri-moto
 
+# Release 3.7
+
+* replace jscad/modeling with Manifold project for faster mesh boolean
+
 
 # Release 3.6 (2022-10-22)
 
diff --git a/src/add/manifold.js b/src/add/manifold.js
deleted file mode 100644
index 77abbd66..00000000
--- a/src/add/manifold.js
+++ /dev/null
@@ -1,114 +0,0 @@
-/** Copyright Stewart Allen -- All Rights Reserved */
-
-"use strict";
-
-const testing = false;
-
-// dep: ext.manifold
-gapp.register("add.manifold", [], (root, exports) => {
-    Module.onRuntimeInitialized = () => {
-        Module.setup();
-
-        if (testing) {
-            // let c = Module.cube([1,1,1], true);
-            let c = Module.sphere(10, 100);
-            let l = 1000;
-            let cm = c.getMesh();
-            let md = c.getMeshDirect();
-            console.log({ c, cm, md });
-
-            console.time('getMesh');
-            for (let i=0; i<l; i++) c.getMesh();
-            console.timeEnd('getMesh');
-
-            console.time(`getMeshDirect`);
-            for (let i=0; i<l; i++) c.getMeshDirect({ mode: 0 });
-            console.timeEnd(`getMeshDirect`);
-
-            console.time(`getMeshDirect`);
-            for (let i=0; i<l; i++) c.getMeshDirect({ mode: 1 });
-            console.timeEnd(`getMeshDirect`);
-
-            console.time(`getMeshDirect`);
-            for (let i=0; i<l; i++) c.getMeshDirect({ mode: 2 });
-            console.timeEnd(`getMeshDirect`);
-        }
-    };
-
-    function indexVertices(pos) {
-        mesh.log(`indexing ${pos.length/3} vertices`);
-        let ipos = 0;
-        const index = [];
-        const vertices = [];
-        const cache = {};
-        const temp = { x: 0, y: 0, z: 0 };
-        for (let i=0, length = pos.length; i<length; ) {
-            temp.x = pos[i++];
-            temp.y = pos[i++];
-            temp.z = pos[i++];
-            let key = [
-                ((temp.x * 100000) | 0),
-                ((temp.y * 100000) | 0),
-                ((temp.z * 100000) | 0)
-            ].join('');
-            let ip = cache[key];
-            if (ip >= 0) {
-                index.push(ip);
-            } else {
-                index.push(ipos);
-                cache[key] = (ipos++);
-                vertices.push(temp.x, temp.y, temp.z);
-            }
-        }
-        return { index, vertices };
-    }
-
-    function pos2mesh(pos) {
-        const { index, vertices } = indexVertices(pos);
-        const mesh = {
-            vertPos: new Module.Vector_vec3(),
-            triVerts: new Module.Vector_ivec3(),
-            vertNormal: new Module.Vector_vec3(),
-            halfedgeTangent: new Module.Vector_vec4()
-        };
-        for (let i = 0, l = vertices.length; i < l; ) {
-            mesh.vertPos.push_back({
-                x: vertices[i++],
-                y: vertices[i++],
-                z: vertices[i++]
-            });
-        }
-        for (let i = 0, l = index.length; i < l; ) {
-            mesh.triVerts.push_back([ index[i++], index[i++], index[i++] ]);
-        }
-        return mesh;
-    }
-
-    function mesh2pos(mesh) {
-        const { vertPos, triVerts } = mesh;
-        const vertices = new Float32Array(triVerts.length * 9);
-        for (let i = 0, t = 0, l = triVerts.length; t < l; t++) {
-            let tri = triVerts[t];
-            let vert = vertPos[tri[0]]; // X
-            vertices[i++] = vert[0];
-            vertices[i++] = vert[1];
-            vertices[i++] = vert[2];
-            vert = vertPos[tri[1]]; // Y
-            vertices[i++] = vert[0];
-            vertices[i++] = vert[1];
-            vertices[i++] = vert[2];
-            vert = vertPos[tri[2]]; // Z
-            vertices[i++] = vert[0];
-            vertices[i++] = vert[1];
-            vertices[i++] = vert[2];
-        }
-        return vertices;
-    }
-
-    exports({
-        indexVertices,
-        pos2mesh,
-        mesh2pos
-    });
-
-});
diff --git a/src/geo/csg.js b/src/geo/csg.js
index 085095b3..a5a6ef2b 100644
--- a/src/geo/csg.js
+++ b/src/geo/csg.js
@@ -3,7 +3,7 @@
 "use strict";
 
 // dep: geo.base
-// dep: add.manifold
+// dep: ext.manifold
 gapp.register("geo.csg", [], (root, exports) => {
 
 const { base } = root;
@@ -16,10 +16,14 @@ const CSG = {
         mesh.log(`manifold.union ${arguments.length} meshes`);
         const args = [...arguments].map(a => new Module.Manifold(a));
         const result = Module.union(...args);
-        const output = result.getMesh();
+        const output = result.getMesh({ mode: 2 });
+        const errors = [ ...args, result ].map(m => m.status().value);
         for (let m of [ ...args, result ]) {
             m.delete();
         }
+        if (errors.reduce((a,b) => a+b)) {
+            throw `${errors}`;
+        }
         return output;
     },
 
@@ -29,7 +33,7 @@ const CSG = {
         mesh.log(`manifold.subtract ${arguments.length} meshes`);
         const args = [...arguments].map(a => new Module.Manifold(a));
         const result = Module.difference(...args);
-        const output = result.getMesh();
+        const output = result.getMesh({ mode: 2 });
         for (let m of [ ...args, result ]) {
             m.delete();
         }
@@ -41,23 +45,137 @@ const CSG = {
         mesh.log(`manifold.intersect ${arguments.length} meshes`);
         const args = [...arguments].map(a => new Module.Manifold(a));
         const result = Module.intersection(...args);
-        const output = result.getMesh();
+        const output = result.getMesh({ mode: 2 });
         for (let m of [ ...args, result ]) {
             m.delete();
         }
         return output;
     },
 
-    toPositionArray(geom) {
-        return add.manifold.mesh2pos(geom);
+    toPositionArray(mesh) {
+        const { vertPos, triVerts, vertex, index } = mesh;
+        if (vertex) {
+            return vertex;
+        }
+        const vertices = new Float32Array(triVerts.length * 9);
+        for (let i = 0, t = 0, l = triVerts.length; t < l; t++) {
+            let tri = triVerts[t];
+            let vert = vertPos[tri[0]]; // X
+            vertices[i++] = vert[0];
+            vertices[i++] = vert[1];
+            vertices[i++] = vert[2];
+            vert = vertPos[tri[1]]; // Y
+            vertices[i++] = vert[0];
+            vertices[i++] = vert[1];
+            vertices[i++] = vert[2];
+            vert = vertPos[tri[2]]; // Z
+            vertices[i++] = vert[0];
+            vertices[i++] = vert[1];
+            vertices[i++] = vert[2];
+        }
+        return vertices;
     },
 
-    fromPositionArray(array) {
-        return add.manifold.pos2mesh(array);
+    fromPositionArray(pos) {
+        const { index, vertices } = indexVertices(pos);
+        const mesh = {
+            vertPos: new Module.Vector_vec3(),
+            triVerts: new Module.Vector_ivec3(),
+            vertNormal: new Module.Vector_vec3(),
+            halfedgeTangent: new Module.Vector_vec4()
+        };
+        for (let i = 0, l = vertices.length; i < l; ) {
+            mesh.vertPos.push_back({
+                x: vertices[i++],
+                y: vertices[i++],
+                z: vertices[i++]
+            });
+        }
+        for (let i = 0, l = index.length; i < l; ) {
+            mesh.triVerts.push_back([ index[i++], index[i++], index[i++] ]);
+        }
+        return mesh;
     }
 
 };
 
+function indexVertices(pos) {
+    mesh.log(`indexing ${pos.length/3} vertices`);
+    let ipos = 0;
+    const index = [];
+    const vertices = [];
+    const cache = {};
+    const temp = { x: 0, y: 0, z: 0 };
+    for (let i=0, length = pos.length; i<length; ) {
+        temp.x = pos[i++];
+        temp.y = pos[i++];
+        temp.z = pos[i++];
+        let key = [
+            ((temp.x * 100000) | 0),
+            ((temp.y * 100000) | 0),
+            ((temp.z * 100000) | 0)
+        ].join('');
+        let ip = cache[key];
+        if (ip >= 0) {
+            index.push(ip);
+        } else {
+            index.push(ipos);
+            cache[key] = (ipos++);
+            vertices.push(temp.x, temp.y, temp.z);
+        }
+    }
+    return { index, vertices };
+}
+
+function pos2mesh(pos) {
+
+}
+
+Module.onRuntimeInitialized = () => {
+    Module.setup();
+
+    if (false) {
+        let c = Module.cube([1,1,1], true);
+        console.log({
+            c,
+            cm: c.getMesh(),
+            cm0: c.getMesh({ normal: false, mode: 0 }),
+            cm1: c.getMesh({ normal: false, mode: 1 }),
+            cm2: c.getMesh({ normal: false, mode: 2 }),
+            cmn0: c.getMesh({ normal: true, mode: 0 }),
+            cmn1: c.getMesh({ normal: true, mode: 1 }),
+            cmn2: c.getMesh({ normal: true, mode: 2 })
+        });
+
+        let l = 5000;
+        let s = Module.sphere(10, 100);
+        let sm = s.getMesh();
+        console.log({
+            s,
+            sm,
+            md0: s.getMesh({ mode: 0 }),
+            md1: s.getMesh({ mode: 1 }),
+            md2: s.getMesh({ mode: 2 }),
+        });
+
+        console.time('getMesh');
+        for (let i=0; i<l; i++) s.getMesh();
+        console.timeEnd('getMesh');
+
+        console.time(`getMeshDirect`);
+        for (let i=0; i<l; i++) s.getMesh({ mode: 0 });
+        console.timeEnd(`getMeshDirect`);
+
+        console.time(`getMeshDirect`);
+        for (let i=0; i<l; i++) s.getMesh({ mode: 1 });
+        console.timeEnd(`getMeshDirect`);
+
+        console.time(`getMeshDirect`);
+        for (let i=0; i<l; i++) s.getMesh({ mode: 2 });
+        console.timeEnd(`getMeshDirect`);
+    }
+};
+
 gapp.overlay(base, {
     CSG
 });
diff --git a/src/mesh/api.js b/src/mesh/api.js
index a302b809..9acaaeea 100644
--- a/src/mesh/api.js
+++ b/src/mesh/api.js
@@ -404,6 +404,11 @@ const tool = {
                 mesh: data
             })]).promote();
             api.selection.set([group]);
+        })
+        .catch(error => {
+            api.log.emit(`union error: ${error}`);
+        })
+        .finally(() => {
             api.log.emit('union complete').unpin();
         });
     },
diff --git a/src/mesh/build.js b/src/mesh/build.js
index 00570d28..53255861 100644
--- a/src/mesh/build.js
+++ b/src/mesh/build.js
@@ -126,11 +126,11 @@ const log = api.log = {
 
     lines: 20,  // max log lines before forced-age out
 
-    emit(msg) {
+    emit() {
         let { age, data, lines, render } = log;
         let now = Date.now();
         data.push({
-            text: `${dbug.since()} | ${msg}`,
+            text: `${dbug.since()} | ${[...arguments].join(' ')}`,
             time: now
         });
         if (api.isDebug) {
diff --git a/src/moto/worker.js b/src/moto/worker.js
index 3e63c9e4..245815e5 100644
--- a/src/moto/worker.js
+++ b/src/moto/worker.js
@@ -84,7 +84,9 @@ const dispatch = exports({
                     send.done(data);
                 }
             } catch (error) {
-                console.trace(error.stack);
+                if (error.stack) {
+                    console.trace(error.stack);
+                }
                 send.error(error.toString());
                 // dispatch.send({ data: {error: error.toString()}, done: true });
             }