diff --git a/src/main/mesh.js b/src/main/mesh.js
index 3c5dddaf..364b35e3 100644
--- a/src/main/mesh.js
+++ b/src/main/mesh.js
@@ -127,33 +127,33 @@ function space_init(data) {
             }
             let { shiftKey, metaKey, ctrlKey, code } = evt;
             switch (code) {
+                case 'KeyD':
+                    if (shiftKey) {
+                        for (let m of selection.models()) {
+                            m.debug();
+                        }
+                    }
+                    break;
                 case 'KeyC':
-                    selection.centerXY().focus();
-                    break;
+                    return selection.centerXY().focus();
+                case 'KeyX':
+                    return api.file.export();
                 case 'KeyV':
-                    selection.focus();
-                    break;
+                    return selection.focus();
                 case 'KeyW':
-                    api.wireframe();
-                    break;
+                    return api.wireframe();
                 case 'KeyG':
-                    api.grid();
-                    break;
+                    return api.grid();
                 case 'KeyB':
-                    selection.boundsBox({toggle:true});
-                    break;
+                    return selection.boundsBox({toggle:true});
                 case 'KeyH':
-                    space.view.home();
-                    break;
+                    return space.view.home();
                 case 'KeyR':
-                    api.tool.repair();
-                    break;
+                    return api.tool.repair();
                 case 'KeyT':
-                    space.view.top();
-                    break;
+                    return space.view.top();
                 case 'KeyZ':
-                    space.view.reset();
-                    break;
+                    return space.view.reset();
             }
         },
         'keydown', evt => {
@@ -172,13 +172,6 @@ function space_init(data) {
                         estop(evt);
                     }
                     break;
-                case 'KeyD':
-                    if (shiftKey) {
-                        for (let m of selection.models()) {
-                            m.debug();
-                        }
-                    }
-                    break;
                 case 'Escape':
                     selection.clear();
                     estop(evt);
diff --git a/src/mesh/api.js b/src/mesh/api.js
index 0d69c0b8..4061d35d 100644
--- a/src/mesh/api.js
+++ b/src/mesh/api.js
@@ -218,7 +218,16 @@ let file = {
     },
 
     export() {
-        console.log('...export todo');
+        let recs = selection.models().map(m => { return {
+            id: m.id, matrix: m.matrix, file: m.file
+        } });
+        api.log.emit(`exporting ${recs.length} model(s)`);
+        moto.client.fn.file_export({
+            recs, format: "obj"
+        }).then(data => {
+            console.log({work_export: data});
+            util.download(data, "export.obj");
+        });
     },
 };
 
@@ -244,7 +253,7 @@ let tool = {
     }
 };
 
-// api is augmented in mesh.build
+// api is augmented in mesh.build (log, modal, download)
 let api = mesh.api = {
     clear() {
         for (let group of group.list()) {
@@ -300,8 +309,8 @@ let api = mesh.api = {
 let deferFn = [];
 let boundsCache = {};
 
+// util functions augmented in build (download)
 let util = mesh.util = {
-
     uuid(segs = 1) {
         let uid = [];
         while (segs-- > 0) {
diff --git a/src/mesh/build.js b/src/mesh/build.js
index 1cb92035..62b6008a 100644
--- a/src/mesh/build.js
+++ b/src/mesh/build.js
@@ -20,6 +20,13 @@ broker.listeners({
 
 let spin_timer;
 
+// add download / blob export to util
+let download = mesh.util.download = (data, filename = "mesh-data") => {
+    let url = window.URL.createObjectURL(new Blob([data], {type: "octet/stream"}));
+    $('download').innerHTML = `<a id="_data_export_" href="${url}" download="${filename}">x</a>`;
+    $('_data_export_').click();
+};
+
 // add modal dialog functions to api
 let modal = mesh.api.modal = {
     show(title, contents) {
@@ -155,7 +162,8 @@ function ui_build() {
         h.div({ id: 'actions' }),
         h.div({ id: 'grouplist'}),
         h.div({ id: 'selectlist'}),
-        h.div({ id: 'logger', onmouseover() { log.show() } })
+        h.div({ id: 'logger', onmouseover() { log.show() } }),
+        h.div({ id: 'download', class: "hide" })
     ]);
 
     let { actions, grouplist, selectlist, logger } = bound;
@@ -174,7 +182,7 @@ function ui_build() {
                     onchange(evt) { broker.send.load_files(evt.target.files) }
                 })
             ]),
-            h.button({ _: 'export', onclick: api.file.export, disabled: true }),
+            h.button({ _: 'export', onclick: api.file.export }),
             h.div({ class: "vsep" }),
             h.button({ _: 'analyze', disabled: true }),
             h.button({ _: 'repair', onclick: api.tool.repair }),
@@ -215,7 +223,9 @@ function ui_build() {
             .map(g => h.div([
                 h.button({ _: `group`, title: g.id,
                     class: [ "group", selHas(g) ? 'selected' : undefined ],
-                    onclick() { api.selection.toggle(g) }
+                    onclick(e) {
+                        e.shiftKey ? api.selection.toggle(g) : api.selection.set([g])
+                    }
                 }),
                 h.div({ class: "vsep" }),
                 h.div({ class: "models"},
diff --git a/src/mesh/model.js b/src/mesh/model.js
index a23cafee..f02b46f1 100644
--- a/src/mesh/model.js
+++ b/src/mesh/model.js
@@ -76,9 +76,13 @@ mesh.model = class MeshModel extends mesh.object {
         return this.mesh;
     }
 
+    get matrix() {
+        return this.mesh.matrixWorld.elements;
+    }
+
     debug() {
         worker.model_debug({
-            matrix: this.mesh.matrixWorld.elements,
+            matrix: this.matrix,
             id: this.id
         }).then(data => {
             // for debugging matrix ops
diff --git a/src/mesh/work.js b/src/mesh/work.js
index b648d1f4..6386ca43 100644
--- a/src/mesh/work.js
+++ b/src/mesh/work.js
@@ -31,6 +31,13 @@ function cacheUpdate(id, data) {
     Object.assign(cache[id], data);
 }
 
+function translate_encode(id, matrix) {
+    let rec = cache[id];
+    let geo = rec.geo.clone();
+    geo.applyMatrix4(core_matrix.clone().multiply( new THREE.Matrix4().fromArray(matrix) ));
+    return geo.attributes.position.array;
+}
+
 let model = {
     load(data) {
         let { vertices, indices, name, id } = data;
@@ -41,7 +48,9 @@ let model = {
     },
 
     debug(data) {
-        let { matrix, id } = data;
+        let { id, matrix } = data;
+        return translate_encode(id, matrix);
+        throw "should not here";
         let rec = cache[id];
         let geo = rec.geo.clone();
         let m4 = core_matrix.clone().multiply( new THREE.Matrix4().fromArray(matrix) );
@@ -108,14 +117,41 @@ let object = {
     }
 };
 
-worker.bind("debug", (data, send) => {
+let file = {
+    export(data, send) {
+        let { format, recs } = data;
+        switch (format) {
+            case "obj":
+                let p = 1;
+                let obj = [];
+                for (let rec of recs) {
+                    let { id, matrix, file } = rec;
+                    let verts = translate_encode(id, matrix);
+                    obj.push(`g ${file}`);
+                    for (let i=0; i<verts.length; p += 3) {
+                        obj.push(`v ${verts[i++]} ${verts[i++]} ${verts[i++]}`);
+                        obj.push(`v ${verts[i++]} ${verts[i++]} ${verts[i++]}`);
+                        obj.push(`v ${verts[i++]} ${verts[i++]} ${verts[i++]}`);
+                        obj.push(`f ${p} ${p+1} ${p+2}`);
+                    }
+                }
+                return obj.join('\n');
+            default:
+                throw `invalid format "${format}"`;
+        }
+    }
+};
+
+function debug() {
     console.log({work_cache: cache});
-});
+}
 
 worker.bindObject({
+    debug,
     model,
     group,
-    object
+    object,
+    file
 });
 
 worker.ready();
diff --git a/src/moto/worker.js b/src/moto/worker.js
index 9af4cc18..073860c3 100644
--- a/src/moto/worker.js
+++ b/src/moto/worker.js
@@ -86,12 +86,13 @@ const dispatch = moto.worker = {
         if (run) {
             try {
                 let data = run(msg.data, send);
-                if (data || async === false) {
+                if (!done && (data || async === false)) {
                     send.done(data);
                 }
             } catch (error) {
                 console.trace(error.stack);
-                dispatch.send({ data: {error: error.toString()}, done: true });
+                send.error(error.toString());
+                // dispatch.send({ data: {error: error.toString()}, done: true });
             }
         } else {
             console.log({worker_unhandled: e});