Circles and Continuity

I was checking the continuity of curves involving circles and lines and found to my shock that places that I expected would get G1 were Go.

In the attached example, I:

  1. drew a perpendicular cross.
  2. drew a circle at the line intersections.
  3. drew a line (green) where the circle intersects the purple line.
  4. split the circle on the purple line.
    Yet the green line and semicircle are G0 when I would expect them to be G1.

How can I ensure such curves are continuous?

Problem Circle.3dm (2.8 MB)

Well the problem seems to be that the circle isn’t actually centered where the lines cross, it’s 1/4" too low. Can’t say what might have caused that, just make sure the “int” snap is the only one active when picking that center point.

Thanks, restarted Rhino, tried again and it worked. For some reason every circle in the original file was 1/4" from the intersection of the center.

It looks like one file was doing something funky. I copied every thing to a new file and have not seen the same.