SYMPTOMS
In some situations when launching Mari you may find that your View Transform Toolbar is unavailable. When this happens, you will not be able to access a few Palettes and the View Transform Toolbar will not load automatically at the bottom of the viewport when launching Mari in its default layout.
CAUSE
The View Transform Toolbar will be unavailable if Mari is unable to locate the PyOpenColorIO module from your $PYTHONPATH location.
If you are unable to access your Python Console, this usually indicates that Mari cannot locate the PyOpenColorIO module, which can be caused by conflicting modules created by multiple different software or by an incorrect $PYTHONPATH file path. Mari by default looks for this module in the following location, but there is a chance that this could be pointing to an incorrect path if you are using a custom environment:
<Mari install location>/Mari7.0v2/Bundle/bin/lib/site-packages
If your $PYTHONPATH is incorrect or conflicting, you may also notice that you have not only lost the View Transform Toolbar but also both the overhead Python and Scripts menus, as well as the Modo Render and Snapshots palettes. This is because each of these palettes are Python-based and make use of the $PYTHONPATH location.
Fig: A standard palette menu and a palette menu with a conflicting $PYTHONPATH
RESOLUTION
The quickest and easiest way to identify whether you are running into a PyOpenColorIO error is to double check your MariLog.txt file.
You may see the following message inside it:
Debug : [ Application.cpp:449 ] : [ OpenColorIO ] [ ERROR ] Failed to load Python bindings '/path/to/problematic/library:
undefined symbol: _ZTIN11OpenColorIO2v19ExceptionE'
This indicated that Mari is currently unable to correctly locate the PyOpenColorIO module from your $PYTHONPATH due to other conflicting modules found at this location.
To confirm this, you should locate the path for this module and check that your PYTHONPATH environment variable is pointing to the correct location. At this stage it's also useful to confirm that PYTHONHOME is set correctly.
To do this, run the following script in Mari's Python Console which will return the variable value:
import os
print os.environ.get("PYTHONPATH")
print os.environ.get("PYTHONHOME")
Using the results, you should be able to confirm that both the PYTHONHOME and PYTHONPATH variables are pointing to the correct module. If this is not the case, you can correct them by setting their value to the right location. By default Mari expects the $PYTHONPATH location in the following directory or similar:
<Mari install location>/Mari7.0v2/Bundle/bin/lib/site-packages
Once the environment variables are corrected and Mari is relaunched, you should see that your View Transform Toolbar and other Python-based palettes have reappeared and are available for use once more.
FURTHER HELP
If you have tried all of the steps detailed above but still find that you are unable to locate your View Transform Toolbar, please create a support ticket and provide us with the information requested in this article:
Q100090: Information to send Support when reporting a Mari issue
For more information on how to open a Support ticket, please refer to this article:
Q100064: How to raise a support ticket
We're sorry to hear that
Please tell us why