I have drawn and assembly, part of which is 6" tubes connected at the corners to form a rectangle the sides of which are 34'x27'. The tubes are flexible and curved gently upward between the corners of the rectangle. At one corner of the rectangle I've drawn a triangle with the "spline on surface" tool. Leg A of the triangle runs along the top of the tube that is the longer side of the rectangle for about 6'. Another leg of the triangle (leg B) is drawn on the top surface of the tube for about 6', that is the short side of the subject rectangle. These two splines are joined at the corner of the rectangle to form one vertex of the triangle. A simple spline in space was drawn to connect the other ends of leg A and lag B to form leg C of the triangle. We now have a triangle drawn with splines with two slightly curved legs (A and B) and one straight leg C. This drawing was made in assembly mode. I want to copy this drawing to a new file where I can use it as a sketch for a surface sweep. I try to do this by left clicking on the sketch in the feature tree of the assembly, then click edit- copy. Then I open a new part file. When I click Edit and Paste in the new part file, I get a message saying "Drag and drop failed" . When I click OK a second message says "The item on the clip board cannot be pasted here". I've tried to paste the drawing to the new part window in "Sketch" mode, "3-D Skecth" mode and out of sketch mode. I think it can be done because when first began playing around with it I did manage to copy two legs of the triangle on one occasion, but I don't remember how I did it. What am I doing wrong?