Technically, I have a problem. I have this thing that I made. I am sure there is a better way to do this, but it is almost done and I have the shape I want, I just don’t know how to fill in the curved portion so that it is solid. I tried model repair but it has no clue.
The basic procedure is referred to as “hand-stitching,” which consists of using the Line tool to connect the vertices (endpoints) of the curves in such a manner as to form a network of triangles describing the compound curved surface. To make the endpoints easier to see, I’ve turned on endpoint display (at value 2) and exploded the curves, as shown in the picture.
Typically, you need to subdivide the mesh down to triangles to form faces, which by definition are coplanar and therefore always support a face, although you can see that at least one face formed over a quadrilateral. When you’re done making the network of faces, you can use the Soften/Smooth command to hide the edges and cause the surface to appear smooth and continuous.
Toggle the Styles dialog box and click Edit, then check the Endpoints box as shown highlighted in yellow. You can enter any value of your choice, any integer greater than 1 will probably yield a good result in this case.