topic Re: Drawing Tangent Lines in Documentation

Drawing Tangent Lines

Anonymous — Mon, 03 Feb 2025 15:49:31 GMT

I've hit upon an annoying defficiency in ArchiCAD, again, and I'm wondering if anybody out there has a solution (aka: workaround).

How do you draw a line that's tangent to two circles? I have a site plan with property lines at some odd angles which are not dimensioned. All I have to go on is some dimensions that locate the corner of the building. Going the reverse route, I need to ... [long story short] ... draw a line that's tangent to 2 circles.

I've tried two different ways of constructing the tangent line geometrically, but the solution always ends up being "slighly" off (depending on the scale. For a site plan you're talking feet - a considerable problem).

So does anybody have any suggestions?

Thanks in advance.

Re: Drawing Tangent Lines

Anonymous — Sat, 05 Jun 2004 15:53:58 GMT

Here it is

Re: Drawing Tangent Lines

Djordje — Sun, 06 Jun 2004 18:24:41 GMT

Sergio wrote:
How do you draw a line that's tangent to two circles?

http://archicad-talk.graphisoft.com/viewtopic.php?t=485

http://archicad-talk.graphisoft.com/viewtopic.php?p=2456#2456

HTH,

Re: Drawing Tangent Lines

Steve Jepson — Mon, 07 Jun 2004 03:20:41 GMT

Djordj,

I don't think the illustrations you posted work.

The line the illustration makes is only part of the process.
The line proposed will create chords across two circles. (sometimes very small) However, it is the perpendicular bisector of these chords the will locate the true points tangent.