INTERSECTION AND DEVELOPMENT OF SURFACES
SURFACES
A surface is a geometric shape having two dimensions with negligible thickness but it may lie in a three dimensional space. The surface may be formed/generated by moving a line, called the GENERATRIX of the surface. Any position of the generatrix is an element of the surface. The line showing path of motion of the generatrix is called the DIRECTRIX. The surface generated by moving a straight line along any path is called a RULED SURFACE.
The surface generated by moving a straight line generatrix parallel to its original position along a straight path is called a PLANE.
A SINGLE-CURVED SURFACE is a ruled surface that may be generated by moving a straight line along some curved path; examples are the cylinder and the cone.
