How to find the apex of a subtle curve?

Any insight into how to do this?

I need to make a horizontal line that is tangent to the apex of a subtle curve… but I’m struggling to find the highest point. It’s too flat to see on screen.

Can eyeball it good enough for this job but… made me scratch my head about how you would do this perfectly if you were making something that had to be really precise for like a telescope part or something high tech.

The Quadrant osnap will find the maximum/minimum point on a curve or surface edge.

Is that what you’re after?



I’ve never thought to apply that to anything but a circle! Seems obvious now. Thanks John.

Thanks for that, John. I never thought of it either.

I appreciate your showing the help, but at first glance I couldn’t really figure out what “relative” to the CCP really meant. The help picture kind of implies that all the curves are on the CP. Does it work if they aren’t? If so, maybe a little better description would make it easier to grasp on first reading.

The CPlane shows local X and Y coordinates. The Quadrant finds the local top/bottom/left/right points.
If you have an object free-floating in space, you would need to move a viewport CPlane to align with your desired reference.

Got it. Thanks. I take it Project doesn’t work with it?

You can Project to a CPlane or onto a surface or mesh.
Totally different thing other than also being current CPlane dependent, like many things in Rhino.