diff --git a/graspnetAPI/utils/eval_utils.py b/graspnetAPI/utils/eval_utils.py
index 1ff4f46..5f5dd37 100644
--- a/graspnetAPI/utils/eval_utils.py
+++ b/graspnetAPI/utils/eval_utils.py
@@ -286,6 +286,7 @@ def collision_detection(grasp_list, model_list, dexnet_models, poses, scene_poin
                 center = transform_points(center, np.linalg.inv(obj_pose)).reshape([3]) # object coordinate

                 R = np.dot(obj_pose[:3,:3].T, R)

                 binormal, approach_angle = matrix_to_dexnet_params(R)

+                binormal = binormal / np.linalg.norm(binormal)

                 grasp = ParallelJawPtGrasp3D(ParallelJawPtGrasp3D.configuration_from_params(

                                             center, binormal, width, approach_angle), depth)

                 dexgrasps.append(grasp)