Join (attach) two curves or surfaces together

Create a new curve or surface by joining together two curves or surfaces.

Choose Object Edit > Attach > Attach.
Pick the first curve, or an edge of the first surface.
Pick the second curve, or an edge of the second surface.
For surfaces, if an edge is obscured you can click the closest isoparametric curve. For curves, click near the end you want to attach.

What if...?

I can’t attach a surface to a trimmed surface?

It is not possible to attach a surface to a surface that has been trimmed.

To attach the two surfaces, you must first remove all the trim operations from the trimmed surface.

Reverse the sequence of trims performed on a surface

The resulting surface is twisted?

When attaching surface edges, try to click near the same end of each edge to prevent twisting.

The resulting surface is the wrong degree or contains multi-knots?

Attaching objects of different degrees will create an object of the higher degree with multi-knots. Match the geometry of the objects before attaching. (See Match the edit point locations of objects for more information.)

The resulting surface has poor continuity where it was attached?

If you attach curves with different degrees, the resulting curve will have the higher degree and contain multi-knots.
Use the Knot Insertion option to reduce some of the problems associated with attaching objects with different endpoint tangent magnitudes or degrees.