Drawing Lines Tangent to Two Circles
I'one thousand using Carlson Survey 2016 with IntelliCAD 8.1. I desire to draw a line that is tangent to two circles, like this.
Tangent Snap works fine in drawing a line "to" a tangent, merely not "from" a tangent. Is at that place an easy way to draw this?
Thanks.
Topic starter Posted : January 13, 2017 4:58 pm
It'southward an easy Calc to go the bearing and missing side. Use the sum of the radii as one leg of an bending side side triangle...
Posted : January 13, 2017 5:10 pm
Get-go the big circle in the radius of the small circle. Draw a line from the eye of the small circle to tangent to the inner big circle. The rest should be apparent.
Posted : January thirteen, 2017 5:35 pm
With the autocad engine in the cogo carte there is a simple routine "tangent line between circles", peachy routine. Hopefully intellecad version has it.
Posted : January thirteen, 2017 half dozen:01 pm
You're sketch is showing one of the internal tangents. To get that, wait at the yellow lines above. I created a random radial on the large circle running SE, then I copied that radial to the small-scale circle but ran it NW and continued the end points of the radials. Observe that the yellowish line intersects the line between the two center points (blackness) at the same place where the ii interior radials (magenta) intersect. Once yous take that intersection signal you can draw a line from there and snap tangent to ane of the circles then extend the line to the other circumvolve and information technology should be tangent to both.
The external tangents are similar but instead of making the two radials on opposite headings, make them parallel like the red radials higher up. Connecting the finish points of the parallel radials and intersecting with a line running through the middle of both circles will create the outer intersection indicate to a higher place. Now yous tin can depict a line from the intersection point and snap tangent to the far circle and trim it at the near circumvolve.
I wish I could claim I knew this earlier you ask the question, but Google and Wikipedia are wonderful teachers.
Posted : January 13, 2017 6:14 pm
The crossing of the magenta lines intersection is the cardinal. It can be synthetic a thousand ways because of its symmetry!
Stephan's method has a weakness when the circles are well-nigh the same size.
I connected the radius points, then constructed diameters of each circumvolve perpendicular to that line (giving an "H" shape).
Drawing a line from 1 diameter extremity to the opposite diameter extremity of the other circle, in effect making an "Ten" out of the "H", gives one way to brand the intersection. Then snap your tangents from there.
This method will piece of work even for equal radius circles!
Posted : Jan 13, 2017 8:32 pm
Years ago in ACAD, y'all but had to do the line control, type, tan, click on one circle, then tan, click on the other, and it would draw the line tangent to both. I tin can't get that to work in Carlson, with embedded ACAD, though.
Posted : Jan 14, 2017 7:16 am
Regular Autocad (I'm in 2009 correct now) generates this geometry with the tangent functions on both ends.
Draw larger circumvolve, and so smaller circle.
Brainstorm LINE command, and snap to TAN of larger circle, then the to signal, snap to the TAN of the smaller circle.
Tangent line between circles is generated, that is identical to the one developed via Stephen Ward'south method.
Does IntelliCAD not provide this functionality?
Posted : January 14, 2017 vii:20 am
I know this thread is really almost how to get the software to do it for you, but I wondered how to do information technology on a calculator.
d = altitude betwixt centers
R = one circle radius
r = other circumvolve radius
a = distance from first circumvolve center to crossing point
Then from similar triangles you can rapidly derive
a = d * R /(r+R)
With that information technology is like shooting fish in a barrel to solve the residual of the triangles.
-----
The first step in derivation is to note that the angles in each triangle are the same, so the sides are proportional.
a/R = (d-a)/r
and the rest is trivial algebra
Posted : January xiv, 2017 7:45 am
epoch date, mail: 409078, member: 485 wrote: Regular Autocad (I'm in 2009 right at present) generates this geometry with the tangent functions on both ends.
Does IntelliCAD not provide this functionality?
I believe this is another small annoying function cut out of the OEM version. AutoCAD may do it equally a reminder that your not using the full version.
Posted : Jan fourteen, 2017 4:21 pm
It is distressing that we have become an regular army of push pushers instead of thinkers. When did we end learning how to practice things starting time instead of expecting to go immediate answers with a few keystrokes.
This goes far beyond surveying and trigonometry. The answer to anything MUST BE hands plant on that magic wad of plastic and electronics that 1 can concur in their hand. Understanding whether or non the answer provided is reasonable has become passe.
Posted : January 14, 2017 vi:48 pm
epoch date, mail: 409078, member: 485 wrote: Regular Autocad (I'1000 in 2009 right now) generates this geometry with the tangent functions on both ends.
Draw larger circle, then smaller circle.
Begin LINE command, and snap to TAN of larger circle, and so the to point, snap to the TAN of the smaller circumvolve.Tangent line betwixt circles is generated, that is identical to the i adult via Stephen Ward'due south method.
Does IntelliCAD not provide this functionality?
I run full AutoCAD, and then normally I just draw a line snapping tangent to both circles. My method above was just a workaround for those who aren't blessed with software that will draw information technology automatically.
Posted : January 14, 2017 6:49 pm
Thanks, guys, for all your responses. There's more than than i way to peel a cat!
As far equally I can tell, IntelliCAD will not snap from a tangent, only to a tangent. It does have the "tangent line betwixt circles" routine BK9196 mentioned.
I love this place.
Topic starter Posted : Jan xiv, 2017 7:09 pm
morillovareat1954.blogspot.com
Source: https://surveyorconnect.com/community/software-cad-mapping/line-tangent-to-two-circles/
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