Surfacing Circles

Stumped by this seemingingly simple task.
Draw a planar circle add surface should be easy

The next task is to bend the circle out of planar so the edges are moved back in top view and then surface that shape.

The final task is a complex defornation caused by dragging points on the cirle all overthe place and then forming a surface

In the real world, a piece of cling film would make a surface in a second. Obviously there are intersecint splines here, but still should be possible esp planar.

If the deformed surface has to look circular from one view,
-then you could make a planar surface.
-rebuild it to have sufficient control points that will allow the desired shape.
-switch on Record History and trim it with the circle without shrinking the surface.
-now, you should be able to switch on control points of the surface and adjust it.

does that work?

Thank you for you reply. I guess I am asking two separate questions.

How to make a surface on a planar circle
How to make a surface on a deformed circle that is not planar in any axis.

Even when I rebuild a circle I am still not able to make a surface. I may be using the wrong tool tho…

Use the PlanarSrf tool for any planar curves.

There are many ways - depending on what the result should be.

For example, to make a circular plane that is not trimmed, you could split the circle in two halves. Rebuild those to degree 3 curves and use the as input for the EdgeSrf command. Then turn on the points of this new surface and place them where you want.

I’m not at all sure if that will get you anything meaningful…

Thankyou for that,

For the deformed circle (in 2or3 dimensions) i cannot cut it in half. It is large and takes a long time to get into shape. when I cut it in half I loose the smoothness where the two halfs connect. Thats why it is a complete circle in the firts instance.
The result I want is a surface whose edges are defined by the circle.
I could add a second curve across the circle to define any bulging, but even then, I cannot get a surface.

Perhaps a loft is what you are looking for…?
If you copy the circle above the first one and a center point above that again, you can use the Loft command [and play with the options] to get a surface that has the first circle as the edge.

Not a loft. That would give me a cylinder.
Im looking for a surface out of a single, closed loop curve in 3D.

Not if you loose loft to a point.

Does the Patch command help here?


oooh… loft to a point… patch command, ket me try them…

Loft to a point does work, but I get a seam and its not really smoothin the way a piece of cling film would be

ding ding ding the winner. exactly what I wanted. Smooth surface in one stroke.

Thank you!