Find ce centre of an arc tangent to 2 cercles....

Discussion in 'AutoCAD' started by hpspt, Apr 17, 2007.

  1. hpspt

    hpspt Guest

    Hello
    I draw a circle at 0,0 r=50
    I draw another circle at 200,0 R=100
    I want to draw an arc perfectly tangent to both circle (in such a way that,
    when finished, the whole looks a little bit like an ellipse quarter)
    arc radius is 400
    How can I find EXACTLY the arc center position?
    Thank you for help

    °^O

    O
    (
    °
     
    hpspt, Apr 17, 2007
    #1
  2. hpspt

    Carl AK Guest

    Hint:
    The center on the unknown arc will be 350 from circle 1 and 300 from
    circle 2.
     
    Carl AK, Apr 17, 2007
    #2
  3. hpspt

    R Wink Guest

    Why don't you just draw an cricle using the TTR option? Start circle
    and enter TTR. Pick the two circles and enter the radius. Then you
    can use the ID and cen commands to find the center of the circle,
    which hapopen to be 181.25,-299.4125,0.
     
    R Wink, Apr 17, 2007
    #3
  4. hpspt

    hpspt Guest

    <> I draw a circle at 0,0 r=50
    <> I draw another circle at 200,0 R=100
    <> I want to draw an arc perfectly tangent to both circle (in such a way
    that,
    <> when finished, the whole looks a little bit like an ellipse quarter)
    <> arc radius is 400
    <> How can I find EXACTLY the arc center position

    <"Carl AK" <> a écrit dans le message de <...
    <Hint:
    <The center on the unknown arc will be 350 from circle 1 and 300 from
    <circle 2.

    You are right
    That's crazy simple but I didn't find it!
    Thank you for your help!

    hpspt
     
    hpspt, Apr 17, 2007
    #4
  5. hpspt

    Dr Fleau Guest

    There are actually many circles which are tangent to 2 others, simulating an
    ellipse; the reason being you can choose tangent points in a more or less
    large section of the circles depending on how far away you are from the
    circles. You will need to determine this variable.

    If both circles on each side are equal, your "ellipse" center will be on a
    perpendicular to the middle point of the circles. The missing point lies
    somewhere along this perpendicular.

    Hope this helps.

    Dr Fléau
     
    Dr Fleau, Apr 19, 2007
    #5
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