Ellipse Arc dimensions in drawings

chris_odom

Hi all, I am trying to dimension an elliptical arc in my OS Drawing.  I figured out how to dimension fully formed ellipses (the Shift+Q command was a big help) and was also able to dimension ellipses where the center point and/or the end points of the major or minor axes coincided with some other geometry in the drawing.  What I still can't figure out is how to dimension an elliptical arc whose axes end points are not coincident with other points.  My sketch and my drawing are shown below.  The ellipse is 50x25 and I am using it to remove the corners of yellow box where it intersects the box.  As you can see, I am able to successfully dimension the semi-minor axis, but nothing I do gives me the semi-major.  I did try the trick of show/hide sketch and show/hide sketch-points from within the drawing (as shown below), but this requires so much space on the drawing.  And if I hide the sketch but show the sketch points, the dimensions become angry-red, as shown, and I think it causes confusion because it is unclear to what they refer.

Is there any way to dimension a partial ellipse like we can a partial circle?  Please?





Thanks!
Chris

S1mon

How would you inspect such an imaginary point?

martin_kopplow

Since ellipses are defined by major and minor diameter, and these define the curvature of the perimeter at all places, dimensioning or at least providing minor and major plus midpoint and angle in a drawing is the only valid method of doing it. If only intersection points were given, the curve would be underdefined.

Unfortunately, there is no ellipse dimensioning tool, and unfortunately too, the center line tools do not recognize ellipses. It might be a good idea to create such tool, that upon selecting an ellipse or part of it, revealed it's center, min and maj points for dimensioning. Could even e a sub option of the circle dim or circle center lines tool.

chris_odom

Thanks, Martin.  I agree with you that there should be a tool.  Appreciate you confirming that it's not a problem on my end.

martin_kopplow said:

Since ellipses are defined by major and minor diameter, and these define the curvature of the perimeter at all places, dimensioning or at least providing minor and major plus midpoint and angle in a drawing is the only valid method of doing it. If only intersection points were given, the curve would be underdefined.

Unfortunately, there is no ellipse dimensioning tool, and unfortunately too, the center line tools do not recognize ellipses. It might be a good idea to create such tool, that upon selecting an ellipse or part of it, revealed it's center, min and maj points for dimensioning. Could even e a sub option of the circle dim or circle center lines tool.