CIRCLE TANGENT TO THREE LINES??? CANYOU DO IT?

[Anonymous]

Can anybody tell me how to draw a circle tangent to three lines or other circles?
I didn't know where to post this question - to Tips and tricks or to Wishes. Or to Wishes never to be...
Every time I need to do it I switch to AutoCAD and copy it back to AC.
So, you can do it in AutoCAD guys...

[Anonymous]

I think this would be good to post to the wish list, but I would expand it to request more drawing methods in general. Like drawing a line that is tangent to two (existing) circles. There must be more but I can't think of them off the top of my head.

Please do post this one (or I will). It would be great to get everyone adding their own missing methods to the list.

BTW: There probably is some way to construct the solution (I haven't the time right now to noodle it out), but you are right, this should just take three clicks. We are (mostly) trying to practice architecture not Pythagorean geometry.

[Laszlo Nagy]

This is how to create a tangent to two circles
Laszlo

[Djordje]

Ladies and gentlement,

the tangent discussion happened extensively at the end of the old Talk and the birth of this one; consequesntly, a well illustrated tips by Alex Schamenek and Stuart James had been posted in the Tips&Tricks forum. Look for the end of last year dates.

Before you post, pleasee read first; search here, and at ArchiGuide. Post only after that. Otherwise a valuable contribution can be lost in the redundant threads. Never mind making my life easier

[Laszlo Nagy]

I think the circle tangent to three line solution was not yet posted.
Here it is.
Laszlo

[Laszlo Nagy]

Here is another one that is a specialized case of the previous one.
Laszlo

[Anonymous]

Thank you Laszlo. Handy methods and easily remembered.

[Djordje]

laszlonagy wrote:
I think the circle tangent to three line solution was not yet posted.

Yep, you are right!

Going to Tips&Tricks now!

[Anonymous]

Does anyone have a solution for a circle tangent to three acrs/circles? Just to two will do too

This is how it is done in AutoCAD

[Anonymous]

Here are some solutions for two and three circle tangents. (It would be nice to have the geometry methods built-in - something to add to the wish list I guess.)

The methods should be mostly obvious from the figures.

The gray arcs are swung using center and radius with numeric entry using the r > value > + method.

The intersections of the gray arcs are the centers of the tangents to two circles.

The three circle tangent is drawn using the three point geometry method to the centers of the arcs between the two circle tangents (light teal arcs).

OOPS... On closer inspection the three circle tangent is not quite accurate. This will require a little closer study.