Trying to Break a Circle

[ziemerd]

I am trying to break a circle so I can make part of the circle have hidden line section and I'm having trouble. Part of the circle is suppose to be behind another part but I can't break it in 2008 like I could in 2005.

 

Here is what I've tried so far:

 

Select Break command to break without creating a gap.

 

Command: _break Select object: (I select the circle I want to break)

Specify second break point or [First point]: _f (this has already scrolled in the command line as if it was already done)

Specify first break point: (I use Osnap to click on a point on the circle and enter)

Arc cannot be full 360 degrees (this has already scrolled in the command line)

 

I tried it again.

 

I select Break command again and typed f to select the first point.

Invalid response. (this already scrolled in the command line)

Specify first fence point: (I choose my first point using Osnap)

Specify next fence point or [undo]: (I select my second point using Osnap)

Specify next fence point or [undo]: (I right click and select enter]

Specify first break point: (I choose my first point using Osnap)

Specify second break point: (I select my second point using Osnap)

 

The whole circle disappeared except where I selected.

 

From AutoCAD Help

To break an object

1. Click Modify menu - > Break.

2. Select the object to break.

By default, the point at which you select the object is the first break point. To select a different pair of break points, enter f (First) and specify the first break point.

3. Specify the second break point.

To break an object without creating a gap, enter @0,0 to specify the previous point.

 

I tried the above from the AutoCAD Help and I get Arc cannot be full 360 degrees.

 

Thanks for the help.

 

Dawn

[ReMark]

The "Arc cannot be full 360 degrees" leads me to believe you picked at the same location on the circle both picks. If you had picked at two different locations AutoCAD would have removed a portion of the circle almost as though you had used the trim command selecting as your trimming object a line that crossed the circle. Just use two identical circles trimming away opposite sections. One stays on the layer that is seen and the other goes on the hidden layer.

[ReMark]

Here's a lisp routine by AfraLISP that will break a circle at two points.

 

http://www.afralisp.net/Tips/code110.htm

[ziemerd]

Thank you so much. I didn't think about using two circles. That worked well but it has raised a new question about hidden lines. I'll have to add a new thread about it.

 

Thanks again.

[eldon]

Breaking a circle can be tricky, because the circle is always drawn anticlockwise, and the first break can leave you with a very small arc if you don't pick in the right direction.

 

Safer would be to offset a line, trim between the lines and then extend the arcs back to the original line

[dbroada]

I get this when I forget that I have my CENTRE osnap on

[ziemerd]

Excellent information. I ended up using the trim command to get the job done.