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  1. #21
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    Quote Originally Posted by rkent View Post
    I am curious as to what you were doing this for? Maybe there is a much simpler method we could clue you into.
    There is no doubt about the latter! I am hesitant to highjack this thread because what I need help with is off this topic. I am drawing patterns for sewing which are drawn using polylines with a combination of lines and arcs. This involves taping the pattern pieces on to a grid sheet then mapping out the polylines, entering them into AutoCad, printing out a sheet of pattern pieces then checking them against the original, then adjusting the grips. The last three steps of printing, checking and adjusting need to be repeated much too often for my liking. Note: I print both the pattern and the grid sheet, this allows me to know exactly where and by how much the drawing needs to be. Lines are easy, for example most times a hemline is straight so it's easy to know whether to move the corner grips up, down, left or right. Sometimes even with lines it would be nice to know where the grips are and granted most times you see where the line changes direction. But if I am trying to create arcs that are as smooth as possible then I often don't know where the grips are.

    I have reached a point where I wonder if it wouldn't work, instead of using arcs, to stay with short lines with grips every half inch or so.

    Obviously what I really need help with is measuring arcs, especially if the drawing needs about half a dozen in succession. Are there on-line tutorials that deal with measuring arcs? I can draw them once I know the starting and midpoints. Or would there be measuring tools you could suggest?

  2. #22
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    I hope you are drawing your pattern on the grid sheet. You can create a layer for your grid and then another layer for the pattern, when you print they are both on the same plot. You can have your grid lines plot light and the pattern lines bold.

    There are dimensioning tools built in to the program, the toolpalette for dims may already be up on your screen. There is one for Raduis and one for Diameter which you can use for your arcs. Lots of other dimensioning functions there as well that you might want to explore.
    Sometimes there's a man... I won't say a hero, 'cause, what's a hero? But sometimes, there's a man. And I'm talkin' about the Dude here. Sometimes, there's a man, well, he's the man for his time and place. He fits right in there. And that's the Dude, in Los Angeles. - The Stranger, The Big Lebowski

  3. #23
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    Quote Originally Posted by rkent View Post
    You can create a layer for your grid and then another layer for the pattern, when you print they are both on the same plot. You can have your grid lines plot light and the pattern lines bold.
    Yes, I am doing that. I even use heavier lines to indicate inches, then lighter lines to indicate 0.1".

    There are dimensioning tools built in to the program,
    I have a lot of use for the measuring tools in AutoCad, that is for measuring the length of lines or polylines, but I can't see how the ones you mention would be helpful for plotting out the arcs on my pattern pieces.

    Try to imagine printing out the letter "s" in a 10" high, script type font then recreating it as a drawing. With some fonts you might manage it with a combination of lines and arcs, but say you are using the one called Freestyle Script where you would need a series of different length arcs. How do you decide where one arc ends and stops?

  4. #24
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    OK, I would use the POINT command with endpoint Osnap. As mentioned earlier use ddptype to set the type of point.

    So after getting the point type set, at the command line type MULTIPLE <hit enter> POINT <hit enter> <start picking endpoints on the arcs> <hit escape to end point command>.

    The DONUT command would also work and you wouldn't have to use the multiple option for the command.
    Sometimes there's a man... I won't say a hero, 'cause, what's a hero? But sometimes, there's a man. And I'm talkin' about the Dude here. Sometimes, there's a man, well, he's the man for his time and place. He fits right in there. And that's the Dude, in Los Angeles. - The Stranger, The Big Lebowski

  5. #25
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    Quote Originally Posted by rkent View Post
    OK, I would use the POINT command with endpoint Osnap.
    Sounds interesting! I will give it a try. Thank you for this.

  6. #26
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    Default Maybe another approach would be more direct?

    Maybe I don't understand, but it sounds like you are physically laying out a pattern on a grid, then trying to transfer that to an AutoCAD drawing. Also, it sounds like you are asking about measuring arcs in these physical patterns. Is that right? If so, then there may be some easier approaches to get it into AutoCAD.

    If you can locate the endpoints of these arcs on the grid, draw a straight line between them, then determine the perpendicular distance from this line to the farthest point on the arc, you can determine its radius. Actually, you can just transfer the measurements into AutoCAD, and let AutoCAD determine the rest.

    For example,
    1. Draw a line connecting the endpoints (you don’t need nodes, just coordinates)
    2. Offset this line the direction and distance you measured above
    3. Start drawing an arc using Startpoint and Endpoint.
    4. Finish the arc by just picking the midpoint of the offset line.
    5. Now grab the midpoint of the arc and drag it to the midpoint of the offset line.

    For more complicated curves, there are splines, etc., but, so far, it doesn’t sound like you need this.

    There may be easier ways to do this, or better explanations, so don’t be afraid to ask.

  7. #27
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    Arc changed to midpoint.PNG

    Here is an example of what I was describing. The final arc should go through pts A, M & B. Determine point C on the physical pattern midway between A & B. Going from C perpendicular to AB will yield point M on the arc. You need to physically measure the distance from C to M, then use this as the offset distance from line AB in AutoCAD. In creating the initial arc in AutoCAD, the location of point P is not super-critical, but it is the midpoint of that initial arc. Grab this grip and drag it to point M, the midpoint on the offset line, and you should be done.

  8. #28
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    Quote Originally Posted by neophoible View Post
    Maybe I don't understand, but it sounds like you are physically laying out a pattern on a grid, then trying to transfer that to an AutoCAD drawing. Also, it sounds like you are asking about measuring arcs in these physical patterns. Is that right?
    Exactly!

    If you can locate the endpoints of these arcs on the grid,
    That is what I need advice on! I'm not sure the words to use to describe this (convex and concave?) but if you know what a sleeve pattern looks like then you will know that the armhole part of the pattern is a polyline that starts with a short line that changes to series of arcs where the center of the circle would be to the left of the arc, then changes to being to the right, then beneath, then to the left again, then to the right again, then the poly line changes back to a line. And preferably I want to do this with as few grips as possible, say around 10 to 12 including the midpoints.

    Once I have taken a guess as to where the endpoints are, your directions are not how I program it into AutoCad but I will certainly give it a try!

    Thank you!

  9. #29
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    Default Second thoughts

    Well, my initial suggestion lends itself more to a fairly well-defined series of arcs, that is, where the endpoints are easily discerned. But after looking at a few sleeve patterns, it seems to me that you may be dealing with curves that lend themselves more to splines or doing a fit curve based on many points. That is, it looks like the radius is changing a lot along the path, even constantly, as on a French curve or an ellipse.

    If this is the case, then, while you will still want to keep your points like rkent is talking about, your idea of plotting several points and drawing straight lines between, might be a good idea. Then, you can try a pline fit curve. However, you would want to keep separate any lines that should stay straight; otherwise it will fit them to the curve as well. Please note that I have very little experience with this, so I recommend you wait for someone else to advise you in this area.



  10. #30
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    Quote Originally Posted by neophoible View Post
    , so I recommend you wait for someone else to advise you in this area.
    I just recently joined this forum and I look forward posting questions because I've had positive experiences with an Microsft Access forum I joined.

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