From FreeCAD Documentation
- There are several ways to invoke the tool:
- Press the Ellipse by center, radius, rim point button.
- Select the Sketcher → Sketcher geometries → Create ellipse by center option from the menu.
- Use the keyboard shortcut: G then E, then E.
- The cursor changes to a cross with the current tool mode icon.
- The Ellipse parameters section (introduced in version 0.22) is added at the top of the Sketcher Dialog.
- Optionally press the M key or select from the dropdown list in the parameters section to change the tool mode:
- Center:
- Pick the center of the ellipse. Or with Pos-OVP: enter its X and/or Y coordinate.
- Pick an endpoint of one of the axes of the ellipse, this also defines one of its radii. Or with Dim-OVP: enter this radius and/or the angle of this axis.
- Pick a point to define the other radius of the ellipse. Or with Dim-OVP: enter this radius.
- Axis endpoints: introduced in version 0.22
- Pick the endpoints of one of the axes of the ellipse, this also defines one of its radii. Or with Pos-OVP: enter their X and/or Y coordinates. No constraints are created for these points.
- Pick a point to define the other radius of the ellipse. Or with Pos-OVP: enter its X and/or Y coordinate. No constraint is created for this point.
- The ellipse is created, including a set of internal geometry (major axis, minor axis and two foci), and applicable Pos-OVP and Dim-OVP based constraints are added.
- If the tool runs in continue mode:
- Optionally keep creating ellipses.
- To finish, right-click or press Esc, or start another geometry or constraint creation tool.