[SOLVED] Error when running scene in python interpreter with SofaPython3 plugin

[timp]

Hi all,

I just installed the SofaPython3 plugin (SP3) with out-of-tree builds following the instructions posted here:

https://github.com/SofaDefrost/plugin.SofaPython3/issues/137

When I open the SP3 examples from within the runSofa GUI everything works just fine. However, running a scene file (-> ReadTheDocs_Example.py) from within a python3 interpreter throws the following error:

`[ERROR] [PluginManager] Plugin not found: “SofaAllCommonComponents”

When I run the example scene ControllerScene.py in the same way, I get a few warnings saying “the library has not been initialized (sofa::simulation::common::init() has never been called, see sofa/helper/init.h)” as well as the error from the PluginManager mentioned before.

I know, the plugin is still work in progress but I was wondering if I am using it correctly? Or did I miss a step in the installation process?
My SOFA version is v19.12.

Thanks for your help!

[jnbrunet]

Hi @Tim,

When you start a scene with the runSofa executable, Sofa looks inside the path “../lib” relative to the runSofa executable path in order to find its core plugins.

When you load Sofa inside a python interpreter, Sofa has no idea where its core plugins are, since the only path it knows is the path of the python executable (/usr/bin/python3).

You can provide the path to Sofa’s plugins by either:

1. Set the environment variable SOFA_ROOT to the location of your Sofa build directory (ie, you should be able to find the Sofa’s plugins in $SOFA_ROOT/lib).

$ export SOFA_ROOT=/home/tim/sofa/build
$ python3
>>> import SofaRuntime
>>> from Sofa.Core import Simulation
>>> root = Simulation.load("scene.py")
>>> root.init()

or

2. Manually add the libraries path to the PluginRepository :

$ python3
>>> from SofaRuntime import PluginRepository
>>> from Sofa.Core import Simulation
>>> PluginRepository.addFirstPath("/home/tim/sofa/build/lib")
>>> root = Simulation.load("scene.py")
>>> root.init()

or

3. Use the AddPluginRepository component in your scene
<AddPluginRepository path="/home/tim/sofa/build/lib" />

[timp]

Hi @jnbrunet,
Thanks for your reply! I cannot test it right now but I will let you know if it worked soon.

[timp]

Hi @jnbrunet,
I added the Sofa build directory to PATH. Trying option 1 gives the following output (same with option 2):

>>> import SofaRuntime
>>> from Sofa.Core import Simulation
[ERROR] [PythonScript] ImportError: cannot import name ‘Simulation’ from ‘Sofa.Core’ (/home/tip/.local/lib/python3.7/site-packages/Sofa/Core.cpython-37m-x86_64-linux-gnu.so)
File “<stdin>”, line 1, in <module>

Thanks for your help!

[jnbrunet]

Hey @timp

My mistake, it is from Sofa import Simulation, and not from Sofa.Core import Simulation.

However, it seems there is a binding error on the return type of the Simulation.load(filename) call. I’ll look into it.

For now, if you want to load this scene, first remove the line
confignode.addObject('RequiredPlugin', name="SofaPython3", printLog=False)
from the ReadTheDocs_Example.py file, go in the example directory and do something like:

$ python3
>>> import Sofa
>>> import Sofa.Gui
>>> import Sofa.Simulation
>>> import SofaRuntime
>>> from ReadTheDocs_Example import createScene
>>> SofaRuntime.importPlugin('SofaOpenglVisual')
>>> root = Sofa.Core.Node()
>>> createScene(root)
>>> Sofa.Simulation.init(root)
>>> Sofa.Gui.GUIManager.Init("example", "qglviewer")
>>> Sofa.Gui.GUIManager.createGUI(root)
>>> Sofa.Gui.GUIManager.SetDimension(1080, 1080)
>>> Sofa.Gui.GUIManager.MainLoop(root)

[timp]

Hey @jnbrunet,

Great, we are getting closer. 😉

Now the only thing that is still complaining is the GUIManager:

>>> Sofa.Gui.GUIManager.Init("example", "qglviewer")
[ERROR]   [GUIManager] No GUI registered.
1

If I type Sofa.Gui.GUIManager.ListSupportedGUI(",") I get an empty string.

Any idea how to fix this? Thanks for your patience.

[jnbrunet]

Did you compile Sofa with the GUI support?

If you go inside your Sofa’s build directory, what is the output of
grep "SOFAGUI_.*VIEWER" CMakeCache.txt

[timp]

Hi @jnbrunet,

The output is

SOFAGUI_QGLVIEWER:BOOL=ON
SOFAGUI_QTVIEWER:BOOL=ON

I am not so sure what you mean by GUI support. But, I did not change any of the preconfigured settings related to the GUI when compiling SOFA. Does that help?

[jnbrunet]

Hi @timp,

Sofa is a framework that can be compiled without GUI, I just wanted to make sure that you compiled the GUI part since Sofa.Gui.GUIManager.ListSupportedGUI returned you an empty string.

I am unsure why you cannot get the GUI running from python, but in any cases, starting the Sofa’s GUI from the python script is probably not a good idea. It will simply steal the thread from python and resume it once you close the GUI. If you want a GUI, you are better off just starting the GUI directly with the runSofa executable (sofa/build/bin/runSofa) and open your python scene from there.

[timp]

Hi @jnbrunet,

Okay, makes sense. For now, I don’t really need to start the GUI from Python, just thought it would be nice to have the option.
Thanks again for the explanation and your help!

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