Cannot compile the source code on Ubuntu 18.04 when trying to use headless rendering

[Mintinson]

Checklist

• I have searched for similar issues.
• For Python 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 cloned Open3D by:

git clone https://github.com/isl-org/Open3D.git
cd Open3D

Follow the tutorial, I Install virtualenv and create an env

sudo apt-get install libosmesa6-dev
sudo apt-get install virtualenv python-pip
virtualenv -p /usr/bin/python3 py3env
source py3env/bin/activate

Then, I build Open3D (on Ubuntu 18.04, with CUDA 11.3) with:

mkdir build
cd build
cmake -DENABLE_HEADLESS_RENDERING=ON \
                 -DBUILD_GUI=OFF \
                 -DBUILD_WEBRTC=OFF \
                 -DUSE_SYSTEM_GLEW=OFF \
                 -DUSE_SYSTEM_GLFW=OFF \
                 ..

Error message

-- Could NOT find Python3 (missing: Development Development.Module Development.Embed) (found suitable version "3.8.0", minimum required is "3.6")
CMake Error at CMakeLists.txt:324 (message):
  BUILD_PYTHON_MODULE=ON requires Python >= 3.6.  Please ensure it is in
  PATH.

Open3D, Python and System information

- Operating system: Ubuntu 18.04
- Python version: Python 3.8.0
- System architecture: x86 
- Is this a remote workstation?: yes 
- How did you install Open3D?: build from source
- Compiler version (if built from source): gcc 7.5

Additional information

from the messeage above, It seems like cmake has detect python3.8, (based on (found suitable version "3.8.0", minimum required is "3.6")) but somehow it just won't keep building the project.

I also check the PATH environment,

/root/Open3D/py3env/bin
/root/Open3D/py3env/bin
/root/.vscode-server/cli/servers/Stable-fabdb6a30b49f79a7aba0f2ad9df9b399473380f/server/bin/remote-cli
/root/miniconda3/bin
/root/miniconda3/condabin

It doesn't seem to have any problem.

[ssheorey]

Hi @Mintinson we do not support Ubuntu 18.04 any more. It is EOL. If you have a fix for this issue, please submit a PR and we will check it out.

PS: This looks like a cmake / Python path problem rather than an Open3D issue. Please check cmake docs for the mechanism that cmake uses to find Python (it can be rather involved).