Summarize the issue and your environments (e.g., "Cannot import ml3d on Ubuntu 20.04 with CUDA") #692

Checklist

• I have searched for similar issues.
• I have tested with the latest development wheel.
• I have checked the release documentation and the latest documentation (for main branch).

Steps to reproduce the issue

I first installed Open3D-ML in a VSCode Juypter Notebook by:

pip install open3d
pip install -r requirements-torch.txt

Then, I ran:

import open3d.ml.torch as ml3d

Error message

---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
Cell In[6], line 1
----> 1 import open3d.ml.torch as ml3d

File c:\Users\chalm\AppData\Local\Programs\Python\Python311\Lib\site-packages\open3d\ml\torch\__init__.py:15
     12 from open3d import _build_config
     14 if not _build_config["Pytorch_VERSION"]:
---> 15     raise Exception('Open3D was not built with PyTorch support!')
     16 _o3d_torch_version = _verp(_build_config["Pytorch_VERSION"])
     17 # Check match with PyTorch version, any patch level is OK

Exception: Open3D was not built with PyTorch support!

Open3D, Python and System information

- Operating system: Windows 11 64-bit
- Python version: Python 3.11.1
- Open3D version: open3d-0.19.0
- System type: x84
- Is this remote workstation?: yes
- How did you install Open3D?: pip

Additional information

When I run print(o3d._build_config), I notice that the wheel does not support pytorch. Is there one avaliable for windows? I could not find one on the releases page.

open3d 0.19.0
{'BUILD_TENSORFLOW_OPS': False, 'BUILD_PYTORCH_OPS': False, 'BUILD_CUDA_MODULE': False, 'BUILD_SYCL_MODULE': False, 'BUILD_AZURE_KINECT': True, 'BUILD_LIBREALSENSE': True, 'BUILD_SHARED_LIBS': False, 'BUILD_GUI': True, 'ENABLE_HEADLESS_RENDERING': False, 'BUILD_JUPYTER_EXTENSION': True, 'BUNDLE_OPEN3D_ML': False, 'GLIBCXX_USE_CXX11_ABI': True, 'CMAKE_BUILD_TYPE': 'Release', 'CUDA_VERSION': '', 'CUDA_GENCODES': '', 'Tensorflow_VERSION': '', 'Pytorch_VERSION': '', 'WITH_OPENMP': True}

I followed the installation instructions here: https://github.com/isl-org/Open3D-ML?tab=readme-ov-file
Thank you!