Locking a group by command or rule
I have an upcoming show where there is a tracking stage element needed, but is only present in act 3, and the rigging system needs to be put in place during a quick change.
Space and time restrictions mean that I cannot get a winch in RORO configuration in the space, so I am planning on using two overhead lifting axes for the effect and diverting them across the floor.
Cueing sequence would be to bring in the points during the change, connect them to the tracking SWR, tension them and then control them from with a group, with one of the axes having a position scale offset as -100%. Ideally I would like the ability to lock this group automatically once the system is in tension to avoid an operator from being able to drive the individual axes. (I have ruled myself into a safe situation with a sim IO and a custom position error function to disable motion if they are out of position to each other, however stopping this from being able to happen in the first place would be even better as an additional control measure.)
Ideally locking a group could be done by both a command that you could create a cue line for, but at the very least a rule action to trigger this change would be ideal. If doing this on the group is too challenging, it would be sufficient to be able to select a group to lock to on the axis, as part of an additional rule action.
Thanks.
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Hi Tom,
I think I understand what you are asking but could you explain what the expected behavior would be if an operator tried to move an axes that was locked to a group?
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In the example above I would not want a user to be able to move either axis individually, as this would either put the system into too much tension, or cause it to go slack.
In other words I would want all motion to be controlled by the group, this would normally be a locked group 'full time' but my use case prohibits this. I want to be able to lock it once the mechanical system is rigged, and on demand within a cue list.
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Would a rule that triggers a stop/estop on both axis if only one moved after the system was connected be sufficient?
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Already in place via custom position error monitoring, however the function of a locked group is to stop this sort of inadvertent action from being possible under normal control.
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I agree it would be handy to have a way to disable axis from non group motion. Until such a feature gets rolled out I would look at two rules to help increase safety.
1- Have a rule that looks at the other winches enable , if Winch A is not enabled stop winch B with a little activation time on there and an enable condition of a sim'ed DO that the system is linked. This should prevent motion unless both axis are enabled within whatever the activation time is.
2- to make a rule to prevent the winches from moving at different speeds would be to compare the velocity. If I understand your set up to track the object across stage at .5 FPS one winch would be moving at .5 FPS and the other at -.5. Have a SIM IO that adds the velocity from winch A and which B together. If that value is ever not zero the winches are moving at different speeds and need to be stopped.
Hopefully some of that helps, of course there are many ways to skin the cat and you might be able to come up with a solution that fits your situation better.1 -
Hi Tom,
I hope you are well.
Had a quick play with this and you could achieve similar behaviour to the group lock using the 'Allow Command Source' rule action in a rule on any axis devices you are seeking to prevent moving from outside group control.
Set whatever conditions work for you and use the action to only allow the desired group instance to act as the command source for axis(es) you care about.
HTH
Best,
Joe
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Nice suggestion Joe! That does indeed de-risk the effect.
Appreciate it.
Tom
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Hi Tom,
I am curious how you want to fire this rule. Would be based on the relative positions of the winches? Would a supervisor turn the functionality on and off?0 -
Hi Phillip,
We operate in a rep environment so are very used to enabling/disabling rules depending on the day. We manage this by having a sim IO device with a bit for every show, and any show specific rules look at this bit as an enable condition. We then use either IO cmd within a cue list to turn them on or off, or use a web panel built specifically for this task,
However for the use case above I have added a digital bit to the IO that deals with the position error monitoring for these axes which will be used to turn both the position error monitoring, and the command source rule. This will enable us to turn this feature on when this part of the show is set, rather than a more 'global' enabling of this rule.
FOr some added context our operators use epiQ/iQ, so we try as far as possible when building things in Nav, for them to be accessible by the operators.
T
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