A 2D sketch is developed along a linear path to a specified distance to create a 3D form
A closed sketch will produce a volume which can add or subtract material
An open sketch will produce a Surface feature or a Thin feature. The thin option thickens an open sketch – useful for sheetmetal parts.
Dashboard
How ‘long’ an extruded volume is and what form the end face of the volume takes is dictated by its Depth Options
‘Extruding’ from/to non planar surfaces
A common form is to cut or protrude a sketched area on a curved, non planar surface. You can only extrude from a planar surface.
Either;
Protruding from the surface
Extrude from a plane above or below the surface through the surface creating material and over building the feature. Then cut the volume using a similiar method which produced the original surface but offset by the required distance.
Cut into the surface
Cut through the surface from a plane above or below the surface. Back fill the cut using a similiar method which produced the original feature but offset by the required distance
Or;
Use the Offset Surface feature