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]

Almost a decade since this thread was started, and still no Archicad update to extend the options for the circle construction tool.
Here's a video of the technique I just came up with for constructing a circle tangent to three lines. I think it's faster than some of the earlier approaches mentioned.
http://www.youtube.com/watch?v=12TegajqE4E
I hope it helps any future searchers

[Barry Kelly]

I would have just bisected the 2 angles between the 3 lines and the intersection of those bisecting lines is the centre for the circle you need.
Barry.

[Anonymous]

Awesome. Happy to use that, thanks Barry.
Wish you'd weighed in with that sometime in the last nine years, before I made a video
Wonder if I should delete it again? Oh well.

[Barry Kelly]

That was the gist of Laszlo's second post except the 3 lines there formed a triangle.
It even works for his example with the parallel lines.

I liked the video.
It is interesting to see other solutions too.
Barry.

[Hmooslechner]

https://www.dropbox.com/s/yvjz025ril226q1/3Circles1InnerCircleConsstruction.jpg

This should show the only way i found.. its german and my english is too poor to translate it .., but it could show You the way..

Maybe a real mathematic-GDL-Guru could develop such a thiing...

[Hmooslechner]

three circles with drifferent radius - 1 inner circle touches each..

This schould be a little work for a real GDL-guru - not me..


Did someone work on this problem?

here the not really simple geometric methode...

https://www.dropbox.com/s/yvjz025ril226q1/3Circles1InnerCircleConsstruction.jpg

There are som other mathematical methodes from Gauss and Descartes which are higher than my mathematic level - so if someone dit it bevore, i easyly could program a graphical user interface...

[Ben Cohen]

Or simply choose the correct construction method and click on the three lines !!

[Barry Kelly]

Show-off!

Funny I always assumed that was tangential to 2 lines then pick a third point.
Just goes to show reading the prompt can help - clearly says pick a third point or tangential line.

Mind you I don't think I have ever needed to use this - that is my excuse.

Barry.

[Anonymous]

Oy vey. I'll get back in my box then.

[Ben Cohen]

hahaha
can't say I have ever need it either.....