PlanningScene should support TIME!

[v4hn]

MoveIt's PlanningScene does not have any concept of time. In itself that's ok, because we want to deal with "snapshots" of a real state in many situations. Trajectories already have their own duration_from_previous fields, so they are handled externally.

But every time you want to synchronize a planning scene between different components you have to explicitly request it again (unless you have access to the memory of "the one true scene" in move_group (or in your moveit_servo loop, or any other module you use a PlanningSceneMonitor as an authority). It would be useful to be able to state "use a PlanningScene from this monitor which is at least as new as `.

The easiest solution I see would be to add a stamp to the PlanningScene structure, or at least to the message. That would be somewhat redundant for C++ trajectories though where scenes could then have stamps but are also associated with durations in the trajectory.

Any other ideas?

[henningkayser]

It would be useful to be able to state use a PlanningScene from this monitor which is at least as new as .

What would change compared to the current behavior? We don't have a scene buffer or something like that. Do you imply adding a buffer to PSM and maybe make it lock-free with that? ;)

The message has stamps for transforms and the RobotState (hidden inside the JointState header). While I think adding a stamp is trivial and doesn't hurt, I'm not sure I follow the use case with the current implementation of the PSM.

[v4hn]

What would change compared to the current behavior?

I'm mostly complaining about a missing interface to tell the PSM to wait until it has a scene with updates until time X. That's required to synchronize scene updates on a move group with external nodes monitoring that scene. the joint state message is not necessarily a workaround because it's time stamp implies the last joint state motion, not the current time of the scene.

it's not an urgent issue for me, but I run into it every now and then.