diff --git a/backend/app/services/render_blender.py b/backend/app/services/render_blender.py
index 2f648c9..50ae7f5 100644
--- a/backend/app/services/render_blender.py
+++ b/backend/app/services/render_blender.py
@@ -612,20 +612,25 @@ def render_cinematic_to_file(
         "--background",
         "--python", str(script_path),
         "--",
-        glb_arg,
-        str(frames_dir),
-        str(width), str(height),
-        engine, str(samples),
-        json.dumps(part_colors or {}),
-        template_path or "",
-        target_collection,
-        material_library_path or "",
-        json.dumps(material_map) if material_map else "{}",
-        json.dumps(part_names_ordered) if part_names_ordered else "[]",
-        "1" if lighting_only else "0",
-        cycles_device,
-        "1" if shadow_catcher else "0",
-        str(rotation_x), str(rotation_y), str(rotation_z),
+        glb_arg,                                          # [0] glb_path
+        str(frames_dir),                                  # [1] frames_dir
+        str(frame_count),                                 # [2] frame_count (480)
+        "0",                                              # [3] degrees (unused, compat)
+        str(width), str(height),                          # [4] width, [5] height
+        engine, str(samples),                             # [6] engine, [7] samples
+        json.dumps(part_colors or {}),                    # [8] part_colors
+        template_path or "",                              # [9] template_path
+        target_collection,                                # [10] target_collection
+        material_library_path or "",                      # [11] material_library
+        json.dumps(material_map) if material_map else "{}", # [12] material_map
+        json.dumps(part_names_ordered) if part_names_ordered else "[]", # [13] part_names
+        "1" if lighting_only else "0",                    # [14] lighting_only
+        cycles_device,                                    # [15] cycles_device
+        "1" if shadow_catcher else "0",                   # [16] shadow_catcher
+        str(rotation_x), str(rotation_y), str(rotation_z), # [17-19] rotation
+        "world_z",                                        # [20] turntable_axis (unused)
+        "",                                               # [21] bg_color (unused)
+        "1" if transparent_bg else "0",                   # [22] transparent_bg
     ]
     if use_usd:
         cmd += ["--usd-path", str(usd_path)]