Snaps with an ellipse

[tgorter]

I need to place new elements along an ellipse. The only snaps it gives me are quadrant snaps ! How do i get Revit to give me nearest or intersection snaps along the ellipse??

[tgorter]

Obviously i have my objects snaps on, so don't tell me that!

[eddy.lermytte]

Drag the green Hidden Lines (left/right - up/down - Not the endpoints) and use the endpoints to position the desk