Below I have illustrated plans, section and elevations of a custom vanity pictured on the left.
The location of where the sections are cut are shown on the plan with a “cut line” and an arrow showing where the cut has been made and which way we are looking at the section.
The elevation shows us what we would see standing in front of the vanity. The location/point of the view is again noted with a circle and arrow on the plan. Referring back to the "cake", if you are looking at the side of the cake and it is a round cake, the drawing of this would be a rectangle. Vertical parallel lines are used as shading to show the curve.