TheSwamp
CAD Forums => CAD General => Topic started by: nobody on January 11, 2017, 07:36:09 PM
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Please see attached. I used to know how to solve this by drawing circles in autocad but I can't remember how anymore. Anyone know how to solve this procedurally in cad? The arcs need to be tangent on both ends with not straight segment in the middle.
The white lines are at different bearings. Hope it makes sense.
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It would be serendipitous for your construction method to work with a random middle ( common) tangent point.
By definition, for adjoining arcs, the arc centres and the common tangent point are collinear.
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I'm sure there is an easier way, but the following demonstrates one possible construction:
(http://lee-mac.com/swamp/4tangentconstruction.gif)
Snapping could have been made easier, but I didn't want to change the zoom in order to keep everything in frame.
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Would blend accomplish this task?
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Wow! Super animation mr. Lee. :wideeyed2: It doesn't have to be lisp all the time..
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I assumed that the radii needed to be equal.
If that is indeed not required, here is my suggestion.
Explanation:
The angle between the red and yellow lines is 90 degrees.
The green circle is user defined.
The cyan circle is a copy of the green one.
The angle between the magenta lines is also 90 degrees.
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I assumed that the radii needed to be equal.
If that is indeed not required, here is my suggestion.
Excellent work Roy. :-)
I think we both followed essentially the same route, but I went the long way about constructing the perpendicular bisectors...
As you've deftly demonstrated, the key to the construction is forming this isosceles triangle:
(http://www.lee-mac.com/swamp/2017-01-13.png)
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Have I ever told you how great you guys are? I might be in love ;) lol jk
Thank you!
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Here is my solution
From two existing lines (Yellow)
Create Xline (bisect) with vertex and the start of the first line that bisects the extension of the first line and the line between the two endpoints (Blue)
Do the same for the other line
Create a circle 3P that uses the two endpoints of the lines and the intersection of the two xlines (Blue)
Any solution can be created where the two arcs will meet at a point on the circle (Cyan)
Cheers Rod