diff --git a/src/main/mesh.js b/src/main/mesh.js
index 892ae9ec..ca7caa2c 100644
--- a/src/main/mesh.js
+++ b/src/main/mesh.js
@@ -284,6 +284,8 @@ function space_init(data) {
                 case 'KeyM':
                     if (shiftKey) return api.tool.merge();
                     return api.tool.mirror();
+                case 'KeyU':
+                    return shiftKey && api.tool.union();
                 case 'KeyA':
                     return shiftKey ? api.tool.analyze() : undefined;
                 case 'KeyR':
diff --git a/src/mesh/api.js b/src/mesh/api.js
index 4c453e45..7db3ca19 100644
--- a/src/mesh/api.js
+++ b/src/mesh/api.js
@@ -312,6 +312,22 @@ let tool = {
         });
     },
 
+    union(models) {
+        models = fallback(models);
+        api.log.emit(`union ${models.length} model(s)`).pin();
+        worker.model_union(models.map(m => {
+            return { id: m.id, matrix: m.matrix }
+        }))
+        .then(data => {
+            let group = api.group.new([new mesh.model({
+                file: `unioned`,
+                mesh: data
+            })]).promote();
+            api.selection.set([group]);
+            api.log.emit('union complete').unpin();
+        });
+    },
+
     duplicate() {
         for (let m of selection.models()) {
             m.duplicate();
diff --git a/src/mesh/build.js b/src/mesh/build.js
index bc5dae63..f7a8ca82 100644
--- a/src/mesh/build.js
+++ b/src/mesh/build.js
@@ -281,8 +281,8 @@ function ui_build() {
             h.button({ _: 'visible', onclick() { selection.visible({ toggle: true }) } }),
             h.button({ _: 'bounds', onclick() { selection.boundsBox({ toggle: true }) } }),
             h.button({ _: 'gridlines', onclick() { api.grid() } }),
-            h.button({ _: 'wireframe', onclick() { api.wireframe() } }),
             h.button({ _: 'normals', onclick() { api.normals() } }),
+            h.button({ _: 'wireframe', onclick() { api.wireframe() } }),
         ]),
         h.div([
             h.div({ _: "edit", class: "head" }),
@@ -291,8 +291,8 @@ function ui_build() {
             h.button({ _: 'regroup', onclick: tool.regroup }),
             h.button({ _: 'merge', onclick: tool.merge }),
             h.button({ _: 'mirror', onclick: tool.mirror }),
+            h.button({ _: 'union', onclick: tool.union }),
             h.button({ _: 'split', onclick: call.edit_split }),
-            h.button({ _: 'invert', onclick: tool.invert }),
         ]),
         h.div([
             h.div({ _: "fix", class: "head" }),
@@ -300,6 +300,7 @@ function ui_build() {
             h.button({ _: 'automatic', onclick: tool.repair }),
             h.button({ _: 'analyze', onclick: tool.analyze }),
             // h.button({ _: 'rebuild', onclick: tool.rebuild }),
+            h.button({ _: 'invert', onclick: tool.invert }),
             h.button({ _: 'clean', onclick: tool.clean }),
         ]),
     ]);