I need to model a single 3D curved body from a series of triangulated bodies from an AutoCAD export. My current process is to trace the perimeter of the surface created by the triangular bodies using a 3D sketch and the spline tool and then use the filled surface command. I also add constraint sketches to the filled surface based off crossmembers in the model. I then use the thicken command to turn the created surface into one single body. The problem I run into is that even using the same process with making a filled surface with constraint sketches, sometimes the surface will fail to generate, but will work other times. Does anyone have any ideas as to why this may happen or any suggestions for a better, more efficient process (my process is fairly time consuming to crate one body).