Movi XL - 360 Roll.

Discussion in 'MōVI XL' started by Aiden Bell, Dec 18, 2019.

  1. Aiden Bell

    Aiden Bell New Member

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    Hello, i am using the Movi XL with movi controller and wheels. I am trying to achieve a 360 Barrel Roll. But i am getting interference from the pan axis. When reading the Black Jack 360 roll guide i stumbled on Vector Roll. which will roll on the axis of the lens no matter which way the camera is pointed.

    My theory for the interference was that the head is trying to compensate and is in Vector Roll mode. So i tested the theory and tilted the camera 30 degree and the roll worked so much better.

    So my question is how do i achieve a simple Barrel Roll?
     
  2. Graham Futerfas

    Graham Futerfas Well-Known Member

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    Are you mounting your Movi 90-degrees forward? So that your Pan motor becomes your Roll Axis? Or are you just trying to do a 360 Roll on the Roll motor mounted normally?

    When you say "Interference", what do you mean? Is it Gimbal Lock? Or something else where the controls don't respond properly?
     
  3. Aiden Bell

    Aiden Bell New Member

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    Hi Graham, thanks for your reply. Yes the Movi is mounted underslung. I'm not using pan as roll,just attempting to do a barrel roll via the roll axis.
    I am operating on the roll axis only. But when I roll roughly 80 degrees the pan axis will move both left and right slightly and is visibly noticeable on camera. It's as if the pan axis is trying to compensate for something.
    The freefly technical team have informed me that the black-jack roll guide is for the Movi pro. But I haven't seen an information for the XL.
     
  4. Graham Futerfas

    Graham Futerfas Well-Known Member

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    That sounds like it could be Gimbal Lock, where two of the axes line up with each other, and then can't figure out how to stabilize.

    One thing I find helps smooth it out is to maintain your tilt and pan pretty level, and just Roll.

    I think 360 Roll was designed to have the Pan axis mounted 90-degrees forward and use it as the Roll motor, so you don't worry about wires getting twisted up. There were a couple of good YouTube videos that Freefly made that discussed some of this. You can watch parts of them at 2x speed to get through them more quickly):



     
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  5. Aiden Bell

    Aiden Bell New Member

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    Thank you Graham. The first video explained gimble lock really well. I now know exactly what my Movi is doing and why. and how best to tackle this problem. Big help. nice one.
     
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