resolve centering model vs group so rotation works

src/main/mesh.js

@@ -103,7 +103,10 @@ broker.subscribe('space_init', data => {
 
 // add object loader
 broker.subscribe('space_load', data => {
-    mesh.api.group.new(data.flat().map(el => new mesh.model(el))).centerXY().floor();
+    mesh.api.group.new(data.flat().map(el => new mesh.model(el)))
+        .centerModels()
+        .centerXY()
+        .floor();
 });
 
 // remove version cache bust from url

src/mesh/group.js

@@ -18,15 +18,25 @@ if (mesh.group) return;
 mesh.group = class MeshGroup extends mesh.object {
 
     // @param group {mesh.model[]}
-    constructor(models) {
+    constructor(models = []) {
         super();
         this.group = new THREE.Group();
         this.models = [];
-        for (let model of (models || [])) {
+        for (let model of models) {
             this.add(model);
         }
     }
 
+    // center objects to group bounds
+    // dependent on first being added to world/scene
+    centerModels() {
+        let bounds = this.bounds();
+        for (let model of this.models) {
+            model.center(bounds);
+        }
+        return this;
+    }
+
     object() {
         return this.group;
     }

src/mesh/object.js

@@ -29,8 +29,14 @@ mesh.object = class MeshObject {
         return this;
     }
 
-    centerXY() {
-        let b = this.bounds();
+    center(bounds) {
+        let b = bounds || this.bounds();
+        this.move(-b.center.x, b.center.y, -b.center.z);
+        return this;
+    }
+
+    centerXY(bounds) {
+        let b = bounds || this.bounds();
         this.move(-b.center.x, b.center.y, 0);
         return this;
     }