Horizontal lines in a plane
Plane is given by points GHI on the cube. Horizontal projection plane is blue face of a cube, frontal projection plane is red face. The base (ground) line x12 is intersection line of projection planes, i.e.. Trace lines of the planes n, p are lines where the plane meets the planes of projections, i.e. and .
- Horizontal line h of a plane is parallel to the blue face.
- The line of steepest descent s is perpendicular to the horizontal line. This line determines the slope angle of the plane.
Planes are aither vertical, horizontal, inclined or oblique. A horizontal plane is any plane parallel with the ground plane . All points in horizontal plane are at the same height or elevation above .
A vertical plane is defined as a plane that is perpendicular to the horizontal (ground) projection plane .
A inclined plane is defined as a plane that is perpendicular to frontal projection plane .
Rules for projections of the planes:
- Trace point of the line in the plane is always on the trace of the plane.
- If a line in a plane appears as a point, the plane appears as an edge.
Edge view
Vertical plane always appears as an edge in the