Making circle using ttr

Hi,

I was trying to use the command circle, but using the ttr mode between two lines that the program had drawn without the user need to select them, but I couldn't do it. I've tried using pickpoints or (entget (entlast)) but with no success. Does anyone know how to do it?

Thanks!

Correct me if I am wrong but I think it requires a format like the return from "entsel"

i.e.

(list [ename] [point])

You might want to look at this thread. -David

http://www.cadtutor.net/forum/showthread.php?t=30948&highlight=circle

I don't know if it is possible but for both of the solutions it reuires the user to select the tangency point from the lines, but it would be ideal for the program that after it makes the lines it automatically draws the circle ttr tangent to the two lines that were made but without making the user chose them. Do you know if it can be done?

Thank you!

I would think you would have to calculate the tangent points based on the circle's radius, and enter these and the radius into the function.

It doesn't look like that you can feed the command an ENAME. -David

Command: ci
CIRCLE Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: ttr

Specify point on object for first tangent of circle: (entlast)
<Entity name: 1c35588>

Requires a TAN object-snap and selection of Circle, Arc, or Line.

It doesn't look like that you can feed the command an ENAME. -David

 

Command: ci
CIRCLE Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: ttr

Specify point on object for first tangent of circle: (entlast)
<Entity name: 1c35588>

Requires a TAN object-snap and selection of Circle, Arc, or Line.

Is this in reply to my post?

If your drawing the two lines then why not calculate say the mid point of the two lines then when TTR asks for pt1 & pt2 (line1 line2) you can give it an answer maybe also osmode to nearest.

It worked for me ?

(setq pt1 (getpoint))

(setq pt2 (getpoint))

(command "circle" "TTR" pt1 pt2 rad)

..after it makes the lines it automatically draws the circle ttr tangent to the two lines that were made but without making the user chose them. Do you know if it can be done?

Yes it can be, using a little geometry. The center of the circle is equidistant between the lines. I'd draw a sketch showing some sines, cosines, tangents etc.. but why take away from your fun?

Thanks people, now I think it is working well, I've had to use the commands fillet and extend to do what I was trying to do with the cricle ttr. Thanks again!