What is it?
A standalone session is a Maya session like any other, with the exception that it doesn't load any UI, so it runs in the background and can only be seen thru the OS task manager. The process may show up as "python", "python interpreter" or "mayapy", depending on your system and Maya version. You need to be sure there's no firewall blocking this process.
How and why animBot uses it?
Currently animBot Anim Recovery as well as the animBot updater uses standalone Maya sessions to perform its thing. By doing that, the processes will use separate threads and won't cause freezes or lags the main Maya session, in other words, they run without bothering the user.
Downloading an Update
When animBot is successfully downloading an update, you should expect to see a progress bar on top of animBot's menu button:
* This is an accelerated video, the whole process can take several minutes.
Please read this article for more details about Anim Recovery and standalone Maya sessions.
The downside is that, depending on the user setup, that process can fail :( That means, animBot may not be able to update to a new version within the Maya session or Anim Recovery may not automatically clean up temporary data or be able to fully load checkpoints that are in the past (recovering from a crash should not be affected, as the checkpoints are in the 'future' in comparison with the latest saved Maya scene).
Because a Standalone Maya session doesn't support User Interface (UI), if any UI is launched by ANY tool, it will crash or freeze that Maya session. This is a Maya limitation, not an animBot limitation. Unfortunately Maya is not smart enough to prevent this, so programmers need to implement this by themselves on their tools. Usually big studios take care of those things, but not always, since most of the time users don't use Maya Standalone sessions, unless they use Batch Render or anything specific.
How to test if it's working
From version 2.1.2 or above, run the following tool:
For older versions, do the following:
1. Launch Maya and open any scene. Launch animBot by running the following python command:
import animBot animBot.launch(debugMode=True)
2. Make sure Anim Recovery is on as well as Cleanup Checkpoints:
3. Save your scene. This will spawn the Cleanup Checkpoints process and will freeze Maya for a bit, as it will be watching the standalone Maya session.
4. Keep an eye at the Script Editor for errors.
How to fix problems
In a nutshell, you need to make sure there's no UI being triggered automatically at Maya startup. Things like pickers, anim libraries, aTools or any other third party tool that launches along with Maya will get in the way of a Maya standalone session to work properly. Try looking at the file ..user/maya/scripts/userSetup, usually that's where Maya reads startup scripts/tools.
You can either remove entries from there that launches UIs, or add the following condition, so that it doesn't run on Maya standalone sessions:
if not cmds.about(batch=True): # run your UI
If you are not able to solve it, please report as many details as possible, especially the Script Editor print out as mentioned above to firstname.lastname@example.org