To Create a Section in 2-D Sketcher
1. Sketch the section geometry. The system adds dimensions and constraints automatically as you create the section.
2. To orient the section to be parallel to the screen, click 
Sketch View.
Sketch View.3. To hide the model geometry located in front of the sketching place, in the Graphics toolbar, click 
Clip Model.
Clip Model.4. Redefine the dimensioning scheme, as needed.
You can modify the dimensioning scheme created by Sketcher by adding your own dimensions and constraints. You cannot explicitly delete any system dimensions. As you add dimensions and constraints, the system automatically deletes system (weak) dimensions and constraints that are no longer necessary. If you want to keep the system dimensions and constraints, strengthen them before exiting Sketcher.
5. Add section relations, if desired.
6. Add relations to control the behavior of your section.