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    stephenwyker
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P/T accuracy

I'm sure this has been discussed before, but how does one deal with a college and repeatability? I was to do a 2x6 college (which looked great) but then the client also wanted another look around the room for opening. I didn't think about it until rehearsal and clicked back to the college and all the alignment was off. Not by a lot, but enough that the college couldn't work.

Thought it was my programming, updated and tried again and same situation. Any good advise (besides not moving them)
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    Stephen,

    The best thing to do in this situation is to update each position palette in sequence of the show/cue list.

    For example...

    If cue 1 is your walk-in and cue 2 is your shift to the main look...

    Play cue 1.

    Play cue 2.

    Make very minor position modifications to the position palette in cue 2.

    Repeat.

    This helps to overcome possible hysteresis that is occurring in the position motors. They key here is that the position of a fixture can be affected not only by the absolute position palette but also by the path it takes to get to that position palette. (This is very noticeable in mirrored fixtures, as small discrepancies in pan/tilt motor positions result in much larger/more noticeable position inaccuracy) If you're getting a bad alignment, getting frustrated, releasing your cuelist, sending the fixtures to their 50/50 position, and then updating the position palette, you will probably continue to get a bad alignment coming out of your walk-in look.

    A related note (and something that you may have done already) is that it might be wise to make the position parameters on the DLs non-releasable so that they do no return to their 50/50 positions when you release your list.

    In the case of DLs, I believe that the hysteresis issues were more prominent in DL.1s and early DL.2s than in DL.3s, but I'm not sure on that statement.

    Hopefully this will help a little.

    Good luck and good show!

    PG
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    Stephen,

    The best thing to do in this situation is to update each position palette in sequence of the show/cue list.

    For example...

    If cue 1 is your walk-in and cue 2 is your shift to the main look...

    Play cue 1.

    Play cue 2.

    Make very minor position modifications to the position palette in cue 2.

    Repeat.

    This helps to overcome possible hysteresis that is occurring in the position motors. They key here is that the position of a fixture can be affected not only by the absolute position palette but also by the path it takes to get to that position palette. (This is very noticeable in mirrored fixtures, as small discrepancies in pan/tilt motor positions result in much larger/more noticeable position inaccuracy) If you're getting a bad alignment, getting frustrated, releasing your cuelist, sending the fixtures to their 50/50 position, and then updating the position palette, you will probably continue to get a bad alignment coming out of your walk-in look.

    A related note (and something that you may have done already) is that it might be wise to make the position parameters on the DLs non-releasable so that they do no return to their 50/50 positions when you release your list.

    In the case of DLs, I believe that the hysteresis issues were more prominent in DL.1s and early DL.2s than in DL.3s, but I'm not sure on that statement.

    Hopefully this will help a little.

    Good luck and good show!

    PG
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