diff --git a/release.md b/release.md
index 3a709191..6bcf7a51 100644
--- a/release.md
+++ b/release.md
@@ -27,6 +27,7 @@ Full docs @ https://docs.grid.space/projects/kiri-moto
 * `-` parameterize svg and image import
 * `-` undo / redo for some operations
 * `-` show camera focal point
+* `-` better Z split snapping and split at defined Z index
 
 
 # Release 3.3 (2022-04-01)
diff --git a/src/mesh/api.js b/src/mesh/api.js
index e5e21ac8..ad8d8be7 100644
--- a/src/mesh/api.js
+++ b/src/mesh/api.js
@@ -59,43 +59,48 @@ const selection = {
 
     // @param group {MeshObject[]}
     set(objects, toolist) {
-        selected = objects;
+        // flatten groups into model lists when present
+        selected = objects.map(o => o.models ? o.models : o).flat();
         tools = toolist || [];
         util.defer(selection.update);
     },
 
     // @param group {MeshObject}
-    add(object, tool) {
-        // pendantic code necessary to minimize re-entrant api calls
+    add(object, tool = mode.is([ modes.tool ])) {
+        // when group added, add group models instead
         if (object.models) {
-            // if group, remove discrete selected members
             for (let m of object.models) {
-                if (selected.contains(m)) {
-                    selection.remove(m);
-                    tools.remove(m);
+                selected.addOnce(m);
+                if (tool) {
+                    tools.addOnce(m);
                 }
             }
         } else {
-            // if model, remove selcted group
-            if (selected.contains(object.group)) {
-                selection.remove(object.group);
-                tools.remove(object.group);
+            selected.addOnce(object);
+            if (tool) {
+                tools.addOnce(object);
             }
         }
-        selected.addOnce(object);
-        if (tool) tools.addOnce(object);
         util.defer(selection.update);
     },
 
     // @param group {MeshObject}
     remove(object) {
-        selected.remove(object);
+        if (object.models) {
+            for (let m of object.models) {
+                selected.remove(m);
+                tools.remove(m);
+            }
+        } else {
+            selected.remove(object);
+            tools.remove(object);
+        }
         util.defer(selection.update);
     },
 
     // remove all
     delete() {
-        for (let s of selection.list()) {
+        for (let s of selection.list(true)) {
             selection.remove(s);
             tools.remove(s);
             s.showBounds(false);
@@ -104,13 +109,19 @@ const selection = {
     },
 
     // @param group {MeshObject}
-    toggle(object, tool) {
+    toggle(object, tool = mode.is([ modes.tool ])) {
+        if (object.models) {
+            for (let m of object.models) {
+                if (selected.contains(m)) {
+                    return selection.remove(object);
+                }
+            }
+            return selection.add(object, tool);
+        }
         if (selected.contains(object)) {
             selection.remove(object);
-            tools.remove(object);
         } else {
-            selection.add(object);
-            if (tool) tools.addOnce(object);
+            selection.add(object, tool);
         }
     },
 
diff --git a/src/mesh/build.js b/src/mesh/build.js
index 465ca08f..05b987c5 100644
--- a/src/mesh/build.js
+++ b/src/mesh/build.js
@@ -437,9 +437,7 @@ function ui_build() {
             .map(g => h.div([
                 h.button({ _: g.name || `group`, title: g.id,
                     class: [ "group", selHas(g) ? 'selected' : undefined ],
-                    onclick(e) {
-                        e.shiftKey ? selection.toggle(g) : selection.set([g])
-                    }
+                    onclick(e) { selection.toggle(g) }
                 }),
                 h.div({ class: "vsep" }),
                 h.div({ class: "models"},
@@ -447,12 +445,7 @@ function ui_build() {
                     g.models.map(m => [
                         h.button({ _: m.file || m.id,
                             class: [ selHas(m) ? 'selected' : undefined ],
-                            onclick(e) {
-                                let sel = selection.list();
-                                e.shiftKey || (sel.length === 1 && m === sel[0]) ?
-                                    selection.toggle(m) :
-                                    selection.set([m])
-                            }
+                            onclick(e) { selection.toggle(m) }
                         }),
                         h.button({
                             class: [ 'square' ],
@@ -532,7 +525,7 @@ function ui_build() {
         let g_pos = util.average(s_grp.map(g => g.object.position));
         let g_rot = util.average(s_grp.map(g => g.object.rotation));
         let g_id = s_grp.map(g => g.id).join(' ');
-        let h_grp = sblock('group', g_id, grid(
+        let h_grp = sblock('orient', g_id, grid(
             util.extract(g_pos, map),
             util.extract(g_rot).map(r => (r * rad).round(2).toFixed(map.fixed)),
             und, und, 'group'
@@ -541,17 +534,17 @@ function ui_build() {
         let m_pos = util.average(s_mdl.map(m => m.object.position));
         let m_rot = util.average(s_mdl.map(m => m.object.rotation));
         let m_id = s_mdl.map(m => m.id).join(' ');
-        let h_mdl = sblock('model', m_id, grid(
-            util.extract(m_pos, map),
-            util.extract(m_rot, map)
-        ));
+        // let h_mdl = sblock('model', m_id, grid(
+        //     util.extract(m_pos, map),
+        //     util.extract(m_rot, map)
+        // ));
 
         let bounds = util.bounds(s_mdl);
-        let h_bnd = sblock('box', m_id, grid(
-            util.extract(bounds.min, map),
-            util.extract(bounds.max, map),
-            [ "min", "max" ]
-        ));
+        // let h_bnd = sblock('bounds', m_id, grid(
+        //     util.extract(bounds.min, map),
+        //     util.extract(bounds.max, map),
+        //     [ "min", "max" ]
+        // ));
         let h_ara = sblock('span', m_id, grid(
             util.extract(bounds.center, map),
             util.extract(bounds.size, map),
@@ -591,8 +584,8 @@ function ui_build() {
         // bind elements to selectlist div
         let bound = h.bind(selectlist, [
             ...h_grp,
-            ...h_mdl,
-            ...h_bnd,
+            // ...h_mdl,
+            // ...h_bnd,
             ...h_ara,
             ...h_msh,
             ...h_ops