Sketcher > Creating a Feature Section > About Using Sketcher to Create a Feature Section
  
About Using Sketcher to Create a Feature Section
When you create features, often you must sketch sections to define the feature geometry. Sketch only what is necessary. If you do not want to create a new surface, do not sketch a line in the section, and leave the section open. If there is a problem intersecting the feature with the part, you must close the section. When sketching on the model, you use the same tools as standalone Sketcher, plus additional techniques.
 
In Piping, you can use the centerlines of pipe segments as references in the 3-D Sketcher just as you use curves in the following descriptions.
You cannot import any IGES features into Sketcher environment.