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How to draw 2 circle that will meet in their radius

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sunggus

How to draw 2 circle that will meet in their radius

Two circles meet at their radius distance

Say I would like to draw two circles with different diameter or radius. As in the picture, say that the diameter (D1) = 60, Diameter 2 (D2) = 40 (hence R1=30, R2=20). So, the distance between their center will be 30+20=50, as they meet exactly in one point. The two circles are drawn above the same plane, say, above a horizontal plane. I tried 4 tangential options from circle drawing menu, but didn't work. Of course I can do it by do some maths. But what I am asking here is how to do without doing that math, just as simple as using that tangential.

Best regard,

perepujal

Re: How to draw 2 circle that will meet in their radius

El dj. 09 de 04 de 2020 a les 07:26 -0700, en/na sunggus [via LibreCAD]
va escriure:

>
>
> Say I would like to draw two circles with different diameter or
> radius. As in the picture, say that the diameter (D1) = 60, Diameter
> 2 (D2) = 40 (hence R1=30, R2=20). So, the distance between their
> center will be 30+20=50, as they meet exactly in one point. The two
> circles are drawn above the same plane, say, above a horizontal
> plane. I tried 4 tangential options from circle drawing menu, but
> didn't work. Of course I can do it by do some maths. But what I am
> asking here is how to do without doing that math, just as simple as
> using that tangential.
>
> Best regard,
>

What version of LibreCAD?, in what OS?

For me it works as following (LibreCAD 2.1.3 on Linux Debian Sid):

draw a horizontal line (the plane)
draw a tangential cicle to that line (the first circle, here I miss a
tangential radius command)
click on tangential 2 circles radius, select the circle and the line as
first and second circles and write the radius size in the box.

Yes, I know it is not obvious to select the line when the command tells
you it needs a circle :)

HTH
Pere

sunggus

Re: How to draw 2 circle that will meet in their radius

draw a tangential circle to that line

perepujal wrote

El dj. 09 de 04 de 2020 a les 07:26 -0700, en/na sunggus [via LibreCAD]
va escriure:
>
>
> Say I would like to draw two circles with different diameter or
> radius. As in the picture, say that the diameter (D1) = 60, Diameter
> 2 (D2) = 40 (hence R1=30, R2=20). So, the distance between their
> center will be 30+20=50, as they meet exactly in one point. The two
> circles are drawn above the same plane, say, above a horizontal
> plane. I tried 4 tangential options from circle drawing menu, but
> didn't work. Of course I can do it by do some maths. But what I am
> asking here is how to do without doing that math, just as simple as
> using that tangential.
>
> Best regard,
>

What version of LibreCAD?, in what OS?

For me it works as following (LibreCAD 2.1.3 on Linux Debian Sid):

draw a horizontal line (the plane)
draw a tangential cicle to that line (the first circle, here I miss a
tangential radius command)
click on tangential 2 circles radius, select the circle and the line as
first and second circles and write the radius size in the box.

Yes, I know it is not obvious to select the line when the command tells
you it needs a circle :)

HTH
Pere

I use LC 2.1.3 under Windows. But I guess that should not be problem.

"Draw a tangential cicle to that line", of course I can do it, but I can not select my own radius.

Best regard,

dellus

Re: How to draw 2 circle that will meet in their radius

For tangential circle to line with radius you can use Circle 2Points (diameter instead of radius, second point @0,60).

sunggus

Re: How to draw 2 circle that will meet in their radius

It is asked to specify the first point of the tangential:

"Specify the first point of the tangential circle."

That's the thing I don't know (without doing math).

Best regard,

sunggus

Re: How to draw 2 circle that will meet in their radius

In reply to this post by dellus

What I expect is, by drawing the first circle and the horizontal plane, to do the second circle I just need to put its radius, the CAD will automatically adjust to have 2 tangential points.

Best regard,

LordOfBikes

Re: How to draw 2 circle that will meet in their radius

Administrator

That's exactly how the above recommended tool Tangential, 2 Circles, Radius works.
Maybe you have missed the change in tool option bar when that tool is active. There you enter the desired radius, then select the circle and line.
Now you should see two white dots which represent the center of possible tangent circles.
Move the mouse near to the wanted circle to get a preview and click once again to finally place the tangent circle.

See also: https://librecad.readthedocs.io/en/latest/ref/tools.html#circle

Armin

^{investing less than half an hour into Search function can save hours or days of waiting for a solution}

sunggus

Re: How to draw 2 circle that will meet in their radius

Thank you very much. Yes, it is, I missed the field to put the radius. It work perfectly.

Best regard,