remove model loading on startup

app.py

@@ -28,6 +28,9 @@ os.environ['NUMBA_THREADING_LAYER'] = 'workqueue'
 download_scenedino_checkpoint("ssc-kitti-360-dino")
 download_scenedino_checkpoint("ssc-kitti-360-dinov2")
 
+net_v1, renderer_v1, ray_sampler_v1 = None, None, None
+net_v2, renderer_v2, ray_sampler_v2 = None, None, None
+
 
 def convert_voxels(arr, map_dict):
     f = np.vectorize(map_dict.__getitem__)
@@ -61,6 +64,9 @@ def demo_run(image: str,
              y_range: int, 
              z_range: int):
 
+    if net_v1 is None:
+        load_scenedino()
+
     if backbone == "DINO (ViT-B)":
         net, renderer, ray_sampler = net_v1, renderer_v1, ray_sampler_v1
     elif backbone == "DINOv2 (ViT-B)":
@@ -191,10 +197,6 @@ def demo_run(image: str,
     return output_2d, glb_path
 
 
-net_v1, renderer_v1, ray_sampler_v1 = None, None, None
-net_v2, renderer_v2, ray_sampler_v2 = None, None, None
-load_scenedino()
-
 demo = gr.Interface(
     demo_run,
     inputs=[