diff --git a/src/lib/exportSelectionGLB.ts b/src/lib/exportSelectionGLB.ts
new file mode 100644
index 0000000..1b91297
--- /dev/null
+++ b/src/lib/exportSelectionGLB.ts
@@ -0,0 +1,46 @@
+import * as THREE from 'three';
+import { GLTFExporter } from 'three/examples/jsm/exporters/GLTFExporter.js';
+
+/**
+ * Export the given root objects (already cloned or live in scene) as a single
+ * binary GLB, preserving each one's current world transform. Triggers a
+ * browser download.
+ */
+export async function exportObjectsAsGLB(
+  objects: THREE.Object3D[],
+  fileName: string
+): Promise<void> {
+  if (objects.length === 0) return;
+
+  const scene = new THREE.Scene();
+  for (const src of objects) {
+    src.updateWorldMatrix(true, false);
+    const clone = src.clone(true);
+    // Bake world matrix into the clone so the export is position-correct
+    // regardless of parent chain.
+    clone.matrix.copy(src.matrixWorld);
+    clone.matrix.decompose(clone.position, clone.quaternion, clone.scale);
+    clone.matrixAutoUpdate = true;
+    scene.add(clone);
+  }
+
+  const exporter = new GLTFExporter();
+  const glb = await new Promise<ArrayBuffer>((resolve, reject) => {
+    exporter.parse(
+      scene,
+      (res) => resolve(res as ArrayBuffer),
+      (err) => reject(err),
+      { binary: true }
+    );
+  });
+
+  const blob = new Blob([glb], { type: 'model/gltf-binary' });
+  const url = URL.createObjectURL(blob);
+  const a = document.createElement('a');
+  a.href = url;
+  a.download = fileName.endsWith('.glb') ? fileName : `${fileName}.glb`;
+  document.body.appendChild(a);
+  a.click();
+  a.remove();
+  setTimeout(() => URL.revokeObjectURL(url), 2000);
+}