Drafting Techniques

[#1]

If I have two circles of unequal diameters and I want to draw a line tangent to them. How is this done?

[#2]

Line command, using the TAN osnap, pick one circle to start, and the second circle to end the the line. 

[#3 · Accepted solution]

Please find the correct anser in the question of 'How to draw a line tangent to two circles?'

in the following link:

https://sites.google.com/site/cadkits/autocad-faq

[#4]

That's an .... "interesting" way to do the task, but its' also a lot more steps that using the tools built into the software to do it simply, with one command, one osnap, and two picks.

[#5]

Mr 3wood, Your solution worked, although a bit lengthy. I thought there may have been a shorter way to do it Others said to use the line command with osnap tangent; click on one circle for start and on the second circle for finish. I tried this, but it doesn't work.

[#6]

Type out the steps you are doing.

LINE <enter>

TAN <enter>

Pick the first point

TAN <enter>

Pick the second point

<enter>

Works like a charm here.

To comment on the OP's answer below:

There is no need to turn off running OSNAPS to acheive this. Just use the Snap: TAN while in the Line Command and a line to tangent will work as needed.

[#7 · Accepted solution]

I just tried it again. I realized that I have to pick only the tangent snap to use with the line command. All other snaps have to be disabled.

[#8]

Not sure this method works in early AutoCAD versions? It works great in AutoCAD 2012 though.

[#9]

It's worked in versions af Acad as far back as I can recall.  Oddly though, using the PLINE command rather than the LINE command does not. work the same way, and will only be tangent to one of the circles.

dunno if it's fair to call that a bug, poor software design, or what, but it does not work as one would expect it to.

[#10]

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ronaldseto wrote:

I just tried it again. I realized that I have to pick only the tangent snap to use with the line command. All other snaps have to be disabled.

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You can force a temporary over-ride of your current object-snap settings by typing in "TAN<enter>" when prompted for any coordinate input. Doing so will, for that input only, disable all other object-snaps, and only look for Tangents. Much faster than manually going into the object snaps dialog every time.

This also works for other object-snaps:

http://www.we-r-here.com/cad/tutorials/level_4/4-2.htm

...and my favorite, M2P!

Typing "M2P<enter>" at a coordinate input prompt will prompt you to pick *TWO* points, and uses the midpoint between them as the single input.

And yes, you can stack snaps inside M2P. For example, you could pick a point that is Midway between 2 Points, one being the virtual INTersection of two non-touching lines, the other being a point that is the CENter of an arc.

...Or you can use it to find the midpoint of the midpoint between two points!!! (AKA the 1/4-point)