The plane on which the projectors meet is known as :

In First Angle Projection, where is the object located in relation to the viewing planes?

It is a type of perspective drawing where all lines from the plan are attached to the SP with projectors:

Two points A and B are in the H.P. The point A is 30 mm in front ofthe V.P., while B is behind the V.P. The distance between their projectorsis 75 mm and the line joining their top views makes an angle of 450 withxy. Find distance of the point B from the V.P.

A drawing which contains views of an object projected onto two or more orthographic planes aExploded View bMultiview Drawing cTechnical Drawing dIsometric Sketching

It is a line parallel to the picture plane base and the ground: