center point of a circle

[Jean Lemire]

Hi folks.

I know it is obvious but just in case.

With exploded circles and arcs, you can use this procedure:

1 - Draw the perpendicular from the midpoint of two adjacent segments. TWo lines to draw.

2 - Their intersection point is the center of the circle.

Just ideas.

[Jim]

Actually, yes. You can draw a 2-segment arc over top of any 2 segments, then use the Point at Center option...

[emerald15]

I know this a rather old thread, but I thought it worth bringing it to the surface for those (like me) who didn't know. Finding the centre of a circle or curve often seems difficult. I've been using the inference technique, but it doesn't always work easily, so I did some searching & arrived here.
And yes, provided Windows>Preferences>Extensions>RubyScript Examples is checked... then you can context click the circle or curve and 'Point to centre'. Hurrah! another gem discovered!

[brookefox]

With exploded circles and arcs, you can use this procedure:

1 - Draw the perpendicular from the midpoint of two adjacent segments. TWo lines to draw.

2 - Their intersection point is the center of the circle.

Just ideas.

Nice tip, Jean. I guess they do not have to be adjacent, even.

[mitcorb]

A little icing on the cake, if you want a plugin:
Chris Fullmer's Exploded Arc Centerpoint Finder. Places a C point where the center of a fragmented arc or circle is supposed to be.

[brookefox]

Thanks, Tim. I can use that one, which I guess uses Jean's method to do the job quicker.

I admire Jean for apparently eschewing the way of methods outside of the native tools as they tend to cloak the logic of the underlying operation, and thus may in some sense be debilitating.

What? Long live the plugin. Long live Jean. Shut up, Brooke.

[mitcorb]

Jean Lemire is one of the most helpful people in this forum. His posts are always enlightening. Thank you, Jean Lemire.