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Eagle snafu,CIRCLE command

Discussion in 'Electronic Design' started by Robert Baer, Dec 3, 2013.

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  1. Robert Baer

    Robert Baer Guest

    The following commands were tried (no more, and no less):
    CHANGE LAYER 121
    CHANGE WIDTH 0.0005
    CIRCLE (0.496 2.842) (1 0)
    Note that last command is EXACTLY from the so-called help; gives
    radius of 2.884957 and if i try CIRCLE (0.496 2.842)(0 0) the result is
    exactly the same.
    The position of the center does have some effect on this bogus
    "diameter".
     
  2. Robert Baer

    Robert Baer Guest

    Now files are getting corrupted during editing.
    SCR commands now have no VISIBLE effect, but Eagle thinks there has
    been a change.
    I only know after the fact - which is when all is settled.
    Real crap!
     
  3. Jasen Betts

    Jasen Betts Guest

    sounds unusual, more people swear by it that at it. perhaps run a
    generic diagnositc like memtest-86+ overnight?
     
  4. Jasen Betts

    Jasen Betts Guest

    oops:

    more people swear by it THAN at it.
     
  5. John S

    John S Guest

    It's doing exactly as it is told. The problem is that the second set of
    enclosed numbers (1 0) is NOT the radius, it is a POINT on the
    circumference. Notice that your circle's circumference passes through
    the point x=1, y=0 in the first case and through x=0, y=0 in the second
    case. Of course, it defines the same circle because one circle passes
    through both points.
     
  6. John S

    John S Guest

    To follow up with an example, if you want a circle with center at
    0.496,2.842 and a 1 inch radius:

    * Make sure your grid is set for inches
    * CIRCLE (0.496 2.842) (1.496 2.842)
     
  7. Looks like the info command does not calculate the radius correctly.
    I tried with various placements, only origin placements give the
    correct radius.

    very Interesting....

    Cheers
     
  8. Robert Baer

    Robert Baer Guest

    Then explain why the CIRCLE (0.496 2.842) (0 0) gives the *same* results.
     
  9. Robert Baer

    Robert Baer Guest

    Well, the "help" indicates that is a diameter...contrary to what you
    say. Vary parameters in the second set and see no or little change.
     
  10. Robert Baer

    Robert Baer Guest

    NOT what the "help" sez....Syntax CIRCLE • •.. [center, circumference]
     
  11. Robert Baer

    Robert Baer Guest

    So the work-around would be to generate wanted circle at 0,0 and then
    move it to correct place.
     
  12. John S

    John S Guest

    Notice it says circumference. Center is a pair of numbers. Circumference
    is a pair of numbers. Diameter or radius would be a single number.
    Circumference is a POINT (x,y) on the circles CIRCUMFERENCE.
     
  13. John S

    John S Guest

    As I said above, it defines the same circle because both (0 0) and (0 1)
    define the (x y) coordinates on the same circle's circumference.
     
  14. John S

    John S Guest

    Help says nothing about the diameter. It indicates a coordinate pair on
    the circumference.
     
  15. John S

    John S Guest

    I gave an example to show how it is done.
     
  16. John S

    John S Guest

    That is one way to do it. But, I gave an example to show you how to do it.
     
  17. John S

    John S Guest

    It says ...[center, CIRCUMFERENCE]. That means two sets of coordinates.
    Let me try this another way...

    What is the radius of a circle whose center is at (0.496 2.842) and
    whose circumference passes through (1 0)? Does the same circle's
    circumference just happen to pass through (0 0)?

    Now try CIRCLE (0.496 2.842) (1.496 2.842) and use the info button to
    read the circle's radius. You will see that it is 1 inch. That's because
    the circumference passes through (1.496 2.842). As you can see, the
    horizontal value 1.496 is one inch greater than 0.496 and the y
    coordinate has not changed.

    This is the way Eagle has done it for over 10 years. It is not the usual
    way CAD programs work, but there you have it.
     
  18. Robert Baer

    Robert Baer Guest

    Words from one "radius", words from another "circumference", words
    from "help" is "circumference" with ZERO examples.
    Results from experimentation so far totally inconsistent with any
    interpretation.
     
  19. Robert Baer

    Robert Baer Guest

    Dew tell.
    Draw a circle with center at x=0.496, y=2.842 and circumference
    crossing x=0, y=0.
    What is the radius? Hint: SQRT(0.496^2 + 2.842^2) or about 2.885.
    Now draw a NEW circle with center at x=0.496, y=2.842 and
    circumference crossing x=0, y=1.
    What is the radius? Hint: a circle of about 1.819 radius; leave
    calculation to the student.
     
  20. Robert Baer

    Robert Baer Guest

    Isn't the radius of a circle one half of the diameter?
    In any case, it talks about the circumference in one breath and the
    radius in another breath.
     
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