Points, Lines, and Planes

Basic Geometric Elements Points, Lines, and Planes Individually Represented

Basic Geometric Elements Normal Edges A normal edge is a line that is perpendicular to a plane of projection. It appears as a point on the plane of projection to which it is perpendicular. It appears as a true length line on the planes of projection to which it is parallel.

Basic Geometric Elements Normal Edges A normal edge is a line that is perpendicular to a plane of projection. It appears as a point on the plane of projection to which it is perpendicular and as a true length line on adjacent planes.

Basic Geometric Elements Inclined Edges An inclined edge is a line that is parallel to a plane of projection but inclined to adjacent planes. An inclined edge appears true length on the plane to which it is parallel and foreshortened on adjacent planes.

Basic Geometric Elements Inclined Edges The true length view of an inclined line is always inclined while the foreshortened views are either vertical or horizontal lines.

Basic Geometric Elements Oblique Edges An oblique edge is a plane that is oblique to all planes of projection. Since it is not perpendicular to any plane it cannot appear as a point in any view. Since it is not parallel to any plane it cannot appear true length in any view. An oblique edge appears foreshortened and in an inclined position in every view.

Basic Geometric Elements Example of Oblique Edges

Basic Geometric Elements Views of Points, Lines and Planes

Basic Geometric Elements Views of Points and Lines

Intersecting Lines

Nonintersecting Lines

Visibility of Nonintersecting Lines

Geometric Constructions Solids Solids bounded by plane surfaces are called polyhedra. The surfaces are called faces. If the faces are equal regular polygons the solids are called regular polyhedra.

Visibility of Nonintersecting lines Visibility of Nonintersecting lines of a Tetrahedron

True Length of an Oblique Line

True Length of an Oblique Line True Length by Revolution

Point View of a Line

Straight Line in a Plane

Point in a Plane

Edge View of a Plane

Piercing Point Piercing Point – Edge View Method

Piercing Point Piercing Point – Cutting Plane Method

Piercing Point Piercing Point – Cutting Plane Method