convert entities

I am trying to import the top half of an airfoil profile into a Parts Studio sketch. I save the top of the airfoil as a polyline and/or a spline in another CAD program as a DXF or DWG. When I go to import the DXF into ONSHAPE, and import it into a sketch, it imports as a series of line segments not a single entity......ie…

Hi, How do I turn a surface to solid? I've got a 'cylindrical' surface created by sweeping an open arc along a closed path . . . how do I close the open ends and create a solid? I guess I can close the open arc and sweep that to create a solid and then boolean fill the centre but that feels like a hack ...

So when I try to make a sketch and use a cylindrical face's top or bottom relative to sketch plane to dimension off of I cant awaken it as a line nor can I use convert entities to make it into a line. This is killing my design intent as I have to dimension off of weird points I put on a while back into my design. Am I…