The revolve feature is very similar to the extrude in that a sketch is developed over a defined distance but in this case the distance is an angle rather than a linear value.
Any angular parameter needs an axis and a zero reference. For the revolve the zero reference is the sketch plane.
Note: If you have elements of your section on the axis then you can only have one curve in that position – you cannot have multiple sketched curves on the axis. All curves must be on one side only of the Axis of Revolution
Axis of Revolution – the line around which the section rotates
The axis can be either;
External – an existing straight edge or datum axis as below. The axis must be on the same plane as the section.
or;
Internal
RMB > Axis of Revolution before creating your section
or;
select an existing centre line > RMB > Designated Axis of Revolution
How far the revolved volume is developed and the shape of its end face is dictated by its Depth Options