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Thread: Straight lines on curved/rippled surfaces? for example: curtain

  1. #1
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    Default Straight lines on curved/rippled surfaces? for example: curtain

    If this question cannot be answered or from what i've heard isn't true, then you can ignore this post.

    So I heard it was possible to calculate curved surfaces like curtains to still be able to project a straight line, or non distorted looking laser graphics.

    Is this really possible???
    if yes how, and how do they do it.... what do they use?

    I'm not sure if I should post this in "advanced" technical discussion.
    But I rather just want to know because I'm curious

    Cheers,

    Pieter

  2. #2
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    Simple enough math, but it will only work for one users line of perspective. You also require the curve details!
    This space for rent.

  3. #3
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    I wonder, but I doubt it... is there maybe an automated solution?
    maybe an array of those ping things that are also available for the arduino.
    they all send out ultrasonic waves and measure distance.
    they can all get very precise distance.
    on curved surfaces they appear closer at some of the pings...
    Likely this wont work because it's not precise though, and only works on the X axis.

    But lets say you calculate it... how do you adjust the projection?

  4. #4
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    Pieter,
    Non-advanced answer: move the curtains...
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  5. #5
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    hehehe I'm not having such a situation.. but I remember seeing the effect of lasering straight lines on a curtain a few times, and I was just curious :P
    but off course I would move the curtains.

  6. #6
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    If the surface is broader; say a curved wall, dome, or just flat but at a dicky angle you can do a *really* good job from the simple geometric correction and project a perfect looking shape.
    I've never found the need in practice to have increased resolution in this respect.

    ...or is this just a thought experiment?
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  7. #7
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    Just look from the same perspective as the projector. Everything will look straight no matter what it's projected on.

  8. #8
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    Quote Originally Posted by drlava View Post
    Just look from the same perspective as the projector. Everything will look straight no matter what it's projected on.
    Har! Perfect math (tm)!
    This space for rent.

  9. #9
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    Quote Originally Posted by danielbriggs View Post
    If the surface is broader; say a curved wall, dome, or just flat but at a dicky angle you can do a *really* good job from the simple geometric correction and project a perfect looking shape.
    I've never found the need in practice to have increased resolution in this respect.

    ...or is this just a thought experiment?
    A experiment is a bit too much, but no it's not needed.
    I was rather wondering

    Quote Originally Posted by drlava View Post
    Just look from the same perspective as the projector. Everything will look straight no matter what it's projected on.
    GENIOUS!

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