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PPT – Orthographic Projection of Lines PowerPoint presentation | free to view - id: 1bf5e5-ZDc1Z

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Orthographic Projection of Lines

- Definition A line may be defined as the path

or locus of a point moving through space. - A straight line segment is the shortest distance

between its end points.

Classification of Lines

- Lines are classified according to the plane or

planes of projection to which they are parallel. - The classifications are Horizontal, Front,

Profile, Vertical, and Oblique, lines.

Classification of Lines

- A Horizontal line is parallel to the Horizontal

plane of projection.

Classification of Lines

- A Front line is parallel to the Frontal plane of

projection.

Classification of Lines

- A Profile line is parallel to the Profile plane

of projection.

Classification of Lines

- A Vertical line is parallel to the Frontal and

Profile planes of projection.

Classification of Lines

- A Oblique line is not parallel to any of the

principal planes of projection.

True Length of a line

- An Oblique line can not be measured in either of

the given views because it is not true length.

True length of a line

- The true length of any line in space is found

only upon a plane of projection parallel to the

line. - We must locate a hinge line parallel to one of

the oblique lines and project it into that plane.

True Length of a line

- Place the hinge line parallel to FH and GH.

True Length of a line

- Project perpendicular to the Auxiliary 1 plane.

True Length of a line

- Locate F1 and G1 in the auxiliary plane.

Point View of a Line

- The Point View of a line is found on a plane that

is perpendicular to the true length image of the

line.

Point View of a Line

- Construct a hinge line perpendicular to the TL

line and project into that plane.

Point View of a Line

- Project perpendicular to the hinge line.

Point View of a Line

- Measure distance from a Related Plane.

Bearing of a Line

- Bearing is the deviation of a line from the

North-South direction. - We will define the bearing as the acute angle

between the line and a North-South line through

the origin of the line. - The bearing of a straight line can be measured

only in the horizontal projection of the line. - We will select the origin point of a line

alphabetically. For example, given line AF,

BFAF would be the origin because it comes first

in the alphabet.

Bearing of a Line

Bearing of a Line

N 30 E

Origin

Bearing of a Line

N 72 W

Origin

Bearing of a Line

S 14 E

Origin

Bearing of a Line

S 51 W

Origin

Angle of a line.

- Inclination is the deviation of a line from the

horizontal. - The inclination of a line may be measured only in

an ELEVATION view which shows the line in TRUE

LENGTH. - The elevation views are F, P, and any auxiliary

view hinged to the Horizontal plane. - Inclination is expressed as slope angle, slope,

and percent grade.

Angle of a line.

- The angle is positive () if inclined upward or

negative (-) if inclined downward from its

origin. - The Slope Angle of a line is the acute angle

formed between the TL image and a horizontal

plane through its origin.

Angle of a line.

- The angle is positive () if inclined upward or

negative (-) if inclined downward from its origin.

Angle of a line.

- The angle is positive () if inclined upward or

negative (-) if inclined downward from its origin.

Angle of a line.

- Can the angle of line D,C be obtained from the

given views?

Angle of a line.

- ANSWER No. The line is in an elevation plane

but is not from a TL line.

Angle of a line.

- The true angle of a line can only be measure from

an elevation plane and a TL line.

NOT TL

Angle of a line.

- An Oblique line can not be measured in either of

the given views because it is not true length.

Angle of a line.

- Find TL in auxiliary plane 1. Measure from a

horizontal line.

Slope of a line.

- SLOPERISE RUN
- Slope is the tangent of the slope angle

Slope of a line.

- Find TL in auxiliary plane 1. Measure from a

horizontal line.