Cannot import name '_ext' && Pcl install on 18.04 Buntu

Hello,

First of all, thank you for your work.

In the context of a concrete application for my thesis subject I would like to test your PVN3D code. However, I encounter a problem that I can’t correct. Indeed, when using demo_linemod.sh I encounter the following problem :

ImportError: cannot import name '_ext' from 'lib.pointnet2_utils' (/home/tpetitjean/PhD_Thesis/T1Pvn3D/PVN3D/pvn3d/lib/pointnet2_utils/__init__.py)

I’m sure I installed PointNet properly, and built it as indicated. I can see PointNet installed in my Conda env and using the python3 setup.py command build_ext has created a build file inside the PointNet tree.

Do you have any idea what I can do to correct this problem? Is there a file to move by hand after the build? Or is it the build that did not work as expected?

I thank you in advance for your clarification and wish you a very pleasant continuation. Sincerely, Theo

[aiai84]

I saw your words and i think the main problem is the installation of the PCL on Ubuntu 18.04. I install it in two computer, ubuntu 16.04 and 20.04, IN 16.04, it is more easier, It seems that through sudo apt-get install libpcl-all can install . For 18.04 and higher, must through the git method
sudo apt install libpcl-dev libvtk6-dev clone fork with fix for Ubuntu 18.04 git clone https://github.com/Tuebel/python-pcl cd python-pcl python3 setup.py install ` pcl 1.7 is not suitable for 18.04, hope this will help you!

[liupenglei]

I have the same problem, did you manage to solve this issue ?

Hi, yes i did, some point are explained here, if you can’t fix it with my previous answer, be sure to notify me, and i’ll do my possible to make the solution bit more clear in order to help there 😉

I solved this problem in a strange way, I installed the tutorial installation, and then Cannot import name’_ext’ appears; the solution: Change from. Import _ext to:

try: from lib.pointnet2_utils import _ext except ImportError: from torch.utils.cpp_extension import load import glob import os.path as osp import os