Posted by LordOfBikes on Jun 21, 2013; 8:42pm
URL: https://forum.librecad.org/The-drawing-an-elipse-with-four-particular-points-on-the-x-y-aixs-tp5708421p5708425.html

OK Bob, that is what I guessed.

What you need is not an ellipse, you need two ellipse arcs. Use the ellipse arc drawing tool.

First draw two construction lines and use snapping on endpoints and intersection or use the command line to enter the coordinates.

1. Line (-100,-20) (100,-20)
2. Line (0,120) (0,-120)
3. Ellipse arc centre(0,-20) major(0,-120) minor(-100,-20) start angle(-100,-20) end angle(100,-20)
4. Ellipse arc centre(0,-20) major(0,120) minor(-100,-20) start angle(100,-20) end angle(-100,-20)

The lower arc is a circle arc in this case, but maybe this changes in another cut and it is safer to use the ellipse arc.

Have fun constructing all the fuselage sections.

Armin