Tools

Projection of Planes

Theory

Plane

A plane is 2-dimensional figure which has length and breadth. It has no thickness or its thickness is always neglected. A plane can be called a plane surface or figure or lamina or plate. Projection of planes is drawing projections of a 2-dimensional figure on the principal planes of projections. A plane can be represented by the following ways-

  1. Three non-collinear points.
  2. A line and a point not in on the line.
  3. A plane
  4. Two intersection line
  5. Two parallel lines
  6. Strike and dip

Terminologies

1. True shape – The actual shape of the plane is called its true shape.
2. Inclination with the horizontal plane (HP) – It is the acute angle the plane makes with the horizontal plane.
3. Inclination with the vertical plane (VP) – It is the acute angle the plane makes with the vertical plane.
4. Traces of plane - The lines of intersection of the plane with the reference planes (HP or VP).
5. Horizontal Trace (HT) – The real or imaginary line of intersection of a plane with the HP is called horizontal trace of the plane.
6. Vertical Trace (VT) – The real or imaginary line of intersection of a plane with the VP is called vertical trace of the plane.
7. Line view or edge view – The view of a plane seen a line in called line view or edge view of a plane.

Note:

  1. A plane may have horizontal trace, vertical trace or both.
  2. Horizontal trace (HT) is always located in the top view (TV).
  3. Vertical Trace (VT) is always locate in the front view (FV).

Types of Planes

1. Perpendicular Planes

The planes which have their surface perpendicular to any one of the reference planes and parallel or inclines to the other reference plane are called as perpendicular planes.

Example: Surface of a plane inclined to HP and perpendicular to VP, Surface of a plane parallel to VP and perpendicular to HP, etc.

Perpendicular Plane

2. Oblique Planes

The planes which have their surface inclined to both the reference planes.

Example: A plane inclined to both HP and VP

Oblique Plane

Orientation of planes in space

The following positions of planes in space are possible-

  1. Planes Parallel to VP and Perpendicular to HP
  2. Planes Perpendicular to VP and Parallel to HP
  3. Planes Parallel to both VP and HP or both Perpendicular VP and HP
  4. Planes Perpendicular to VP and Inclined to HP
  5. Planes Inclined to VP and Perpendicular to HP
  6. Planes Inclined to both VP and HP

Note: The following notation should be followed while naming different views of projection of planes-

Table