diff --git a/mmpose/datasets/transforms/converting.py b/mmpose/datasets/transforms/converting.py
index d47829d06e..90536bd736 100644
--- a/mmpose/datasets/transforms/converting.py
+++ b/mmpose/datasets/transforms/converting.py
@@ -91,12 +91,10 @@ def transform(self, results: dict) -> dict:
         num_instances = results['keypoints'].shape[0]
 
         # Initialize output arrays
-        keypoints = np.zeros((num_instances, self.num_keypoints, 2))
+        keypoints = np.zeros((num_instances, self.num_keypoints, 3))
         keypoints_visible = np.zeros((num_instances, self.num_keypoints))
+        key = 'keypoints_3d' if 'keypoints_3d' in results else 'keypoints'
 
-        if 'keypoints_3d' in results:
-            keypoints_3d = np.zeros((num_instances, self.num_keypoints, 3),
-                                    dtype=np.float32)
         flip_indices = results.get('flip_indices', None)
 
         # Create a mask to weight visibility loss
@@ -106,43 +104,32 @@ def transform(self, results: dict) -> dict:
         # Interpolate keypoints if pairs of source indexes provided
         if self.interpolation:
             keypoints[:, self.target_index] = 0.5 * (
-                results['keypoints'][:, self.source_index] +
-                results['keypoints'][:, self.source_index2])
-
+                results[key][:, self.source_index] +
+                results[key][:, self.source_index2])
             keypoints_visible[:, self.target_index] = results[
-                'keypoints_visible'][:, self.source_index] * \
-                results['keypoints_visible'][:, self.source_index2]
-
-            if 'keypoints_3d' in results:
-                keypoints_3d[:, self.target_index] = 0.5 * (
-                    results['keypoints_3d'][:, self.source_index] +
-                    results['keypoints_3d'][:, self.source_index2])
-
+                'keypoints_visible'][:, self.source_index] * results[
+                    'keypoints_visible'][:, self.source_index2]
             # Flip keypoints if flip_indices provided
             if flip_indices is not None:
                 for i, (x1, x2) in enumerate(
                         zip(self.source_index, self.source_index2)):
-                    id = flip_indices[x1] if x1 == x2 else i
-                    flip_indices[i] = id if id < self.num_keypoints else i
+                    idx = flip_indices[x1] if x1 == x2 else i
+                    flip_indices[i] = idx if idx < self.num_keypoints else i
                 flip_indices = flip_indices[:len(self.source_index)]
         # Otherwise just copy from the source index
         else:
-            keypoints[:,
-                      self.target_index] = results['keypoints'][:, self.
-                                                                source_index]
+            keypoints[:, self.target_index] = results[key][:,
+                                                           self.source_index]
             keypoints_visible[:, self.target_index] = results[
                 'keypoints_visible'][:, self.source_index]
-            if 'keypoints_3d' in results:
-                keypoints_3d[:, self.target_index] = results[
-                    'keypoints_3d'][:, self.source_index]
 
         # Update the results dict
-        results['keypoints'] = keypoints
+        results['keypoints'] = keypoints[..., :2]
         results['keypoints_visible'] = np.stack(
             [keypoints_visible, keypoints_visible_weights], axis=2)
         if 'keypoints_3d' in results:
-            results['keypoints_3d'] = keypoints_3d
-            results['lifting_target'] = keypoints_3d[results['target_idx']]
+            results['keypoints_3d'] = keypoints
+            results['lifting_target'] = keypoints[results['target_idx']]
             results['lifting_target_visible'] = keypoints_visible[
                 results['target_idx']]
         results['flip_indices'] = flip_indices