diff --git a/scripts/convert_to_robot.py b/scripts/convert_to_robot.py
index fb5651d..31ed0fa 100644
--- a/scripts/convert_to_robot.py
+++ b/scripts/convert_to_robot.py
@@ -17,8 +17,11 @@
 import pickle
 import shutil
 import sys
+import tempfile
 from pathlib import Path
 
+import numpy as np
+
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
 from video2robot.robot import RobotRetargeter
@@ -27,6 +30,35 @@
 from video2robot.utils import get_next_project_dir, emit_progress
 
 
+def prepare_smplx_betas_for_gmr(smplx_path: Path, tmp_dir: Path, target_num_betas: int = 16) -> Path:
+    """Create a temporary SMPL-X file with betas padded/truncated for GMR."""
+    with np.load(smplx_path, allow_pickle=True) as smplx_data:
+        data = {key: smplx_data[key] for key in smplx_data.files}
+
+    betas = np.asarray(data["betas"], dtype=np.float32).reshape(-1)
+    if betas.shape[0] == target_num_betas:
+        return smplx_path
+
+    if betas.shape[0] < target_num_betas:
+        adjusted_betas = np.pad(betas, (0, target_num_betas - betas.shape[0]))
+    else:
+        adjusted_betas = betas[:target_num_betas]
+
+    data["betas"] = adjusted_betas.astype(np.float32)
+
+    tmp = tempfile.NamedTemporaryFile(
+        prefix=f"{smplx_path.stem}_",
+        suffix=".npz",
+        dir=tmp_dir,
+        delete=False,
+    )
+    tmp_path = Path(tmp.name)
+    tmp.close()
+    np.savez(tmp_path, **data)
+    print(f"[SMPL-X] Adjusted betas for GMR: {betas.shape[0]} → {target_num_betas}")
+    return tmp_path
+
+
 def main():
     parser = argparse.ArgumentParser(description="Convert SMPL-X to robot motion")
     
@@ -116,6 +148,8 @@ def main():
     retargeter = RobotRetargeter(robot_type=args.robot)
     motion_paths: dict[int, Path] = {}
     twist_paths: dict[int, Path] = {}
+    temp_smplx_dir = tempfile.TemporaryDirectory(prefix="video2robot_gmr_")
+    temp_smplx_path = Path(temp_smplx_dir.name)
 
     for track in selected_tracks:
         smplx_path = track.smplx_path
@@ -128,8 +162,9 @@ def main():
         if track.track_id:
             print(f"[Robot] Track ID: {track.track_id}")
 
+        gmr_smplx_path = prepare_smplx_betas_for_gmr(smplx_path, temp_smplx_path)
         retargeter.retarget(
-            smplx_path=smplx_path,
+            smplx_path=gmr_smplx_path,
             output_path=output_path,
             target_fps=args.fps,
             visualize=args.visualize,