From e45cf1b74027f0ef876296934dc9c1163e00ed57 Mon Sep 17 00:00:00 2001
From: JingweiZhang12 <zjw18@mails.tsinghua.edu.cn>
Date: Tue, 15 Nov 2022 14:09:12 +0800
Subject: [PATCH] simplify the warning and error when using open3d and
 MinkowskiEngine

---
 mmdet3d/models/backbones/mink_resnet.py       | 9 +++++----
 mmdet3d/models/dense_heads/fcaf3d_head.py     | 6 +++++-
 mmdet3d/models/detectors/mink_single_stage.py | 7 +++++--
 mmdet3d/visualization/local_visualizer.py     | 9 ++++++---
 4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/mmdet3d/models/backbones/mink_resnet.py b/mmdet3d/models/backbones/mink_resnet.py
index e4bae72a87..f295714e6a 100644
--- a/mmdet3d/models/backbones/mink_resnet.py
+++ b/mmdet3d/models/backbones/mink_resnet.py
@@ -5,11 +5,8 @@
     import MinkowskiEngine as ME
     from MinkowskiEngine.modules.resnet_block import BasicBlock, Bottleneck
 except ImportError:
-    import warnings
-    warnings.warn(
-        'Please follow `getting_started.md` to install MinkowskiEngine.`')
     # blocks are used in the static part of MinkResNet
-    BasicBlock, Bottleneck = None, None
+    ME = BasicBlock = Bottleneck = None
 
 import torch.nn as nn
 
@@ -38,6 +35,10 @@ class MinkResNet(nn.Module):
 
     def __init__(self, depth, in_channels, num_stages=4, pool=True):
         super(MinkResNet, self).__init__()
+        if ME is None:
+            raise ImportError(
+                'Please follow `getting_started.md` to install MinkowskiEngine.`'  # noqa: E501
+            )
         if depth not in self.arch_settings:
             raise KeyError(f'invalid depth {depth} for resnet')
         assert 4 >= num_stages >= 1
diff --git a/mmdet3d/models/dense_heads/fcaf3d_head.py b/mmdet3d/models/dense_heads/fcaf3d_head.py
index f43cf698a1..22652e30c6 100644
--- a/mmdet3d/models/dense_heads/fcaf3d_head.py
+++ b/mmdet3d/models/dense_heads/fcaf3d_head.py
@@ -7,7 +7,7 @@
     from MinkowskiEngine import SparseTensor
 except ImportError:
     # Please follow getting_started.md to install MinkowskiEngine.
-    SparseTensor = None
+    ME = SparseTensor = None
     pass
 
 import torch
@@ -69,6 +69,10 @@ def __init__(self,
                  test_cfg: Optional[dict] = None,
                  init_cfg: Optional[dict] = None):
         super(FCAF3DHead, self).__init__(init_cfg)
+        if ME is None:
+            raise ImportError(
+                'Please follow `getting_started.md` to install MinkowskiEngine.`'  # noqa: E501
+            )
         self.voxel_size = voxel_size
         self.pts_prune_threshold = pts_prune_threshold
         self.pts_assign_threshold = pts_assign_threshold
diff --git a/mmdet3d/models/detectors/mink_single_stage.py b/mmdet3d/models/detectors/mink_single_stage.py
index 120743349b..12394fcbc0 100644
--- a/mmdet3d/models/detectors/mink_single_stage.py
+++ b/mmdet3d/models/detectors/mink_single_stage.py
@@ -9,6 +9,7 @@
     import MinkowskiEngine as ME
 except ImportError:
     # Please follow getting_started.md to install MinkowskiEngine.
+    ME = None
     pass
 
 from mmdet3d.registry import MODELS
@@ -56,9 +57,11 @@ def __init__(self,
             test_cfg=test_cfg,
             data_preprocessor=data_preprocessor,
             init_cfg=init_cfg)
+        if ME is None:
+            raise ImportError(
+                'Please follow `getting_started.md` to install MinkowskiEngine.`'  # noqa: E501
+            )
         self.voxel_size = bbox_head['voxel_size']
-        # # TODO: unify the keys
-        # self.head = self.bbox_head
 
     def extract_feat(
         self, batch_inputs_dict: Dict[str, Tensor]
diff --git a/mmdet3d/visualization/local_visualizer.py b/mmdet3d/visualization/local_visualizer.py
index 065683c2dc..5f9f4188ee 100644
--- a/mmdet3d/visualization/local_visualizer.py
+++ b/mmdet3d/visualization/local_visualizer.py
@@ -26,9 +26,9 @@
 try:
     import open3d as o3d
     from open3d import geometry
+    from open3d.visualization import Visualizer
 except ImportError:
-    raise ImportError(
-        'Please run "pip install open3d" to install open3d first.')
+    o3d = geometry = Visualizer = None
 
 
 @VISUALIZERS.register_module()
@@ -126,7 +126,7 @@ def _clear_o3d_vis(self) -> None:
             del self.pcd
             del self.points_colors
 
-    def _initialize_o3d_vis(self, frame_cfg) -> o3d.visualization.Visualizer:
+    def _initialize_o3d_vis(self, frame_cfg) -> Visualizer:
         """Initialize open3d vis according to frame_cfg.
 
         Args:
@@ -136,6 +136,9 @@ def _initialize_o3d_vis(self, frame_cfg) -> o3d.visualization.Visualizer:
         Returns:
             :obj:`o3d.visualization.Visualizer`: Created open3d vis.
         """
+        if o3d is None or geometry is None:
+            raise ImportError(
+                'Please run "pip install open3d" to install open3d first.')
         o3d_vis = o3d.visualization.Visualizer()
         o3d_vis.create_window()
         # create coordinate frame