Hello,

Many thanks for your explanations Michael, this lets me understand and learn a bit more :-)
Both methods (yours and Pilou's one) was very good to make my ellipse perpendicular to my surface.

However I prefer to draw directly on the surface with "object snap" enabled because this surface is not really planar, so drawing directly onto it lets the ellipse axis (say hole axis) exactly perpendicular just as I needed.



Thank you very much again for your so precious help ! :-D

Best thinking and cordially yours,
Guy

<< because this surface is not really planar, so drawing directly onto it lets the ellipse axis (say hole axis) exactly perpendicular just as I needed.

You can have surprise if your "surface is not surface really planar" !
In this case you must take some true marks (repères) somewhere!

(A moins que que " not surface really planar" signifie juste inclinée par rapport aux axes ? )

You know Pilou you can draw an ellipse directly on an egg surface, which is yet less planar than my piece was here ! (I'm joking don't worry ;-)

"not really planar" means "not planar" : my surface is rounded as an extruded circle and a bit like a conic one, also.
Yes, I know, a very complex surface for a so simple piece. O:-)
Anyway as you can see on my image - showing your method at the left and Michael's method at the right - this worked well enough :-)

Well, as you have imagined to be exact the ellipse was not all round touching on the "non-planar" surface, but as you understood I just simply drawn my ellipse with its hot points in touch on the surface, then this was enough to obtain my "perpendicular axis" as well as I needed for perpendicularly cutting as it was done.

Cordially,
Guy

It's for a new concept of trimer patatoes ? :)

lol..............

Peace,
Rich_Art. ;-)

Not for potatoes, but for carrots.
And only those that are cooked.

That is a new concept.
Yes, I know, difficult to understand.
But say "thanks" because it is just for this you are still alive. And after thinking, maybe also a bit because the men in black are so busy nowadays... ;oP

Be quiet,
Guy