See the top rated post in this thread. Click here

Results 1 to 10 of 10

Thread: circles within circles...

  1. #1
    0 Did you find this post helpful? Yes

    Default circles within circles...

    Hi,

    I've been hitting my head against a metephorical wall for the last hour trying to do something which seemed simple

    Okay

    I have a large circle and I want to put a smaller circle inside it so that the quadrant of each circle intersect at the o - Easy.
    Circle2.jpg

    I now want to draw a line parrallel to the centre line of the larger circle but offset (in y direction) by x units - Easy.
    Circle3.jpg

    Now for the tricky bit...

    I want to rotate the smaller circle around so that it remains concentric with the larger circle (easy) and becomes parrallel with the offset line (so far impossible!)

    What am I missing? I have tried everything I can think of: parallel onsap, geometric constraints, etc...

    Thanks

  2. #2
    All AUGI, all the time arshiel88's Avatar
    Join Date
    2005-02
    Location
    Off the Grid
    Posts
    558
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    Quote Originally Posted by IamMichaelPacker747327 View Post
    Hi,

    I've been hitting my head against a metephorical wall for the last hour trying to do something which seemed simple

    Okay

    I have a large circle and I want to put a smaller circle inside it so that the quadrant of each circle intersect at the o - Easy.
    Circle2.jpg

    I now want to draw a line parrallel to the centre line of the larger circle but offset (in y direction) by x units - Easy.
    Circle3.jpg

    Now for the tricky bit...

    I want to rotate the smaller circle around so that it remains concentric with the larger circle (easy) and becomes parrallel with the offset line (so far impossible!)

    What am I missing? I have tried everything I can think of: parallel onsap, geometric constraints, etc...

    Thanks
    Sorry but I don't understand quite well. There seems to be some misunderstandings on the definition of terms.

    1. concentric means sharing the same center. Your circles in the images are not concentric.
    2. a circle cannot be parallel to a line.


    If you mean that the smaller circle remains tangent to bigger circle, and its center passing thru the offset line,
    1. Offset the bigger circle to the smaller circle's center.
    2. The intersection of the new circle and the offset line will be the new center of the smaller circle.

    Welcome to AUGI.
    Last edited by arshiel88; 2012-04-25 at 09:22 AM. Reason: Possible solution

    Shielbern Bolalin
    Architectural 3D Renderer
    ----------------------------------------------------------------------
    “A clever person solves a problem. A wise person avoids it.”

    1879-1955

  3. #3
    Certifiable AUGI Addict tedg's Avatar
    Join Date
    2005-06
    Location
    in the upper right corner
    Posts
    2,612
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    I agree, we may need more clarification.
    But if you mean to move the smaller circle so the inside is tangent with the big circle at the offset line, see my suggestion below.
    Attached Images Attached Images
    Last edited by tedg; 2012-04-25 at 01:53 PM. Reason: spelling error
    Ted
    ____________________________________________________________________________________
    AutoCAD 2013 - REVIT Structure 2013 & 2014 - MicroStation V8i - Windows 7 Professional - (dabble with Inventor Professional 2013)

  4. #4
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    Hi,

    Thanks for your comments you are right, I didn't mean concentric and parallel (clearly too much head bashing!). What I meant was: I want to rotate the small circle around the centre of the large circle so that it ends up being tangent to the offset line.

    Hope that makes more sence?

    Cheers,

  5. #5
    Certified AUGI Addict jaberwok's Avatar
    Join Date
    2000-12
    Location
    0,0,0 The Origin
    Posts
    8,369
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    So, similar to Ted's suggestion but use the "R" (reference) option of the rotate command and pick the intersections shown with green circles.

    tangent.png
    John B

    "You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep-seated need to believe." - Carl Sagan

  6. #6
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    Thanks again, but I still can't quite achieve what I am after, even using th "r" command. What I want is that the smaller circle becomes tangential to the horizontally offset line - see below.
    Circle4.png

    Cheers

  7. #7
    All AUGI, all the time arshiel88's Avatar
    Join Date
    2005-02
    Location
    Off the Grid
    Posts
    558
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    Instead of rotating, recreate the circle using the TTR option. Pick the circle and offset line for the tangents, then enter radius for small circle.

    In case the radius is not a whole number, it is best to pick the radius from the circle itself when asked for the radius, to avoid inaccuracy. (i.e. osnapping NEAREST/QUADRANT to CENTER)
    Last edited by arshiel88; 2012-04-28 at 06:24 AM.

    Shielbern Bolalin
    Architectural 3D Renderer
    ----------------------------------------------------------------------
    “A clever person solves a problem. A wise person avoids it.”

    1879-1955

  8. #8
    100 Club heinsite's Avatar
    Join Date
    2005-11
    Location
    Kona, Hawaii
    Posts
    138
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    Quote Originally Posted by tedg View Post
    I agree, we may need more clarification.
    But if you mean to move the smaller circle so the inside is tangent with the big circle at the offset line, see my suggestion below.
    That's what I thought of first too, but I don't think it's what the OP is after. The problem is the complexity of figuring out what rotation angle to use to get the second circle tangent to the offset line. It doesn't happen where the inside radius intersects the offset.

    The solution instead may be fairly simple as mentioned just above (which I saw after I posted! . Draw the second (smaller) circle using the tan tan radius option. Tangent to the outside circle and tangent to the offset as shown here:

    circle tan-tan-radius.png

    Dave.
    Last edited by heinsite; 2012-04-28 at 06:55 AM.

  9. #9
    1 Did you find this post helpful? Yes

    Default Re: circles within circles...

    Thanks guys. TTR option works a treat!

    Cheers

  10. #10
    Certifiable AUGI Addict tedg's Avatar
    Join Date
    2005-06
    Location
    in the upper right corner
    Posts
    2,612
    0 Did you find this post helpful? Yes

    Default Re: circles within circles...

    Glad we could help, even though it was a long way around to the solution.
    I think a little more info up front would have helped to get there quicker.

    Ted
    ____________________________________________________________________________________
    AutoCAD 2013 - REVIT Structure 2013 & 2014 - MicroStation V8i - Windows 7 Professional - (dabble with Inventor Professional 2013)

Similar Threads

  1. 2012: Concentric Circles
    By dherbstr in forum Dynamic Blocks - Technical
    Replies: 4
    Last Post: 2011-12-02, 07:30 PM
  2. Circles Masking
    By ekolto in forum AutoCAD General
    Replies: 3
    Last Post: 2011-10-25, 07:33 PM
  3. Circles from a list
    By lugligino in forum AutoLISP
    Replies: 6
    Last Post: 2011-10-25, 12:35 PM
  4. Dimensioning Circles
    By mjdanowski in forum Revit MEP - General
    Replies: 10
    Last Post: 2007-04-09, 12:27 PM
  5. Filling circles
    By leosgott in forum AutoCAD Map 3D - General
    Replies: 3
    Last Post: 2005-04-27, 03:27 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •