diff --git a/urdfpy/urdf.py b/urdfpy/urdf.py
index 14b0216..2542ce0 100644
--- a/urdfpy/urdf.py
+++ b/urdfpy/urdf.py
@@ -3472,6 +3472,7 @@ def animate(self, cfg_trajectory=None, loop_time=3.0, use_collision=False):
                 ct = ct.reshape(-1, 1)
             if ct.ndim != 2 or ct.shape[1] != len(self.actuated_joints):
                 raise ValueError('Cfg trajectory must have entry for each joint')
+            traj_len=ct.shape[0]
             ct_np = {j: ct[:,i] for i, j in enumerate(self.actuated_joints)}
         else:
             raise TypeError('Invalid type for cfg_trajectory: {}'