Hey @rav, thanks for the questions and sorry for the late reply; you got me just as I was headed out the door for a long weekend. 
Scenario: We have a team of animators on various shows and not all of them require the use of Ragdoll. Also, we may not need ragdoll during blocking and general “pre-spline-ness”.
That’s an ideal scenario. The intent is for Ragdoll to be at the fingertips of every animator - even with just 1 licence - loaded and menu available, and only occupy a licence when a simulation actually takes place.
Is it possible to drop/release a license without closing the scene?
No, Maya cannot unload any plug-in with nodes still present in a scene. Even if those are only available via undo.
That said, if you remove all nodes (e.g. via the Delete All Physics menu item) and clear your undo then unloading the plug-in should be possible without closing the scene, unloading would automatically drop any activity held less. I haven’t explored this myself so there might be some minutia that I’m missing. Will investigate once I’m back on dry land.
If there are ragdoll nodes in the scene that are not in use, will the lease be dropped automatically?
A licence is dropped under three circumstances.
- Unloading the plug-in
- Manually dropping a licence
- Maya shutdown
It does not keep track of the frequency of use.
In regards to the license server, is there a way to inquire what users have a seat checked out?
The server monitoring mechanism is rather primitive at the moment, but the data is there. Next to the server executable there will be a file called tfs-log.txt. This file contains an entry for every change to your licence allocation since the server was started. Including username, ip and remaining seats. It would be possible to parse this file through e.g. Python to determine the current state. Another option is to launch the server through Python and directly monitor these messages in real-time.
There is an example of such a script here:
I’ve had it on my list to include a more elaborate script/tool like that with Ragdoll, but have found that studios often have their own preference and sometimes their own internal monitoring mechanism with which to integrate with and it’s been hard to capture a one-fits-all list of requirements. But questions like these help, so keep’em coming!
Can the server be set to drop/release a seat after a period of inactivity?
Upon a Maya crash, Ragdoll will have been unable to drop any lease it held. During this kind of inactivity, it will drop a lease automatically. The time between checking for these “zombie” leases can be set in your licence server configuration file, usually around 30 minutes.
But again it does not monitor node usage inside of Maya once a licence had been leased.
From an artist point of view, I can imagine such a mechanism to be quite stressful. To start your day with a licence available only to have it auto dropped while you were working on something else. Are you aware of any other software that does this? I have not come across it before, but it would be technically possible to implement if we found good reason.
If we send a scene to the farm(batch) for export/publishing and there are ragdoll nodes in it (Not in use, cached, off, otherwise transferred to the rig) will it consume a license? And is there control to enable/disable such?
It will not lease any licence unless a simulation takes place. The idea is for Ragdoll to be loaded on every machine in the studio, and only lease a licence on machines that actively use it; including batch licences, where simulation on takes place when recording.
Hope it helps! Let me know if you have any more questions.