Translations:Creating a simple part with Draft and Part WB/39/en

In our case the error is not fixable. It is geometrically impossible to create a solid out of an extruded single line. An extruded line simply becomes a sheet, or shell in FreeCAD lingo. In other words, this is not a FreeCAD limitation, it is a fundamental outcome of geometrical theory. The reason why the 3D view goes completely blank is that the created features, or objects in the Tree View, have errors in the produced shape, and thus contain nothing to render. FreeCAD does however create the new document objects (in this case extrusions) and thus hides any geometry/object used for making the new document objects. That is why the screen goes blank when trying to make a solid out of a line, or lines.