This document defines orthographic drawing and its importance in technical and engineering fields. It explains that orthographic drawing uses multiple views to represent the exact shape and size of an object through lines without shading. It then details the "alphabet of lines" which establishes the different line types used in technical drawings, such as visible, hidden, center, dimension, and leader lines, and defines the purpose of each line type. The document aims to teach the fundamentals and principles of orthographic drawing.

1. Orthographic Drawing
Grade 9 - TLE
Prepred by:
Ms. Arlyn P. Bonifacio
TLE Teacher

2. Objectives
• Define orthographic drawing.
• Explain the importance of the alphabet of
lines in constructing orthographic figures.
• Define pictorial drawing.
• Draw different kinds of pictorial drawing.
• Explain the basic principles of pattern
development.

3. Orthographic Drawing
• The term Orthographic is derived from two
Greek Works:
“Straight”
“to draw”
“…it describes a type of drawing
represented only by lines without shading
or rendering.”

4. What is orthographic Drawing?
Is the method of representing the exact
shape and size of a given object in one or
several views.
Others call it “multi-view drawing” because
it represents not only one but several
views which are projections of an object as
observed in one surface.

5. WHAT IS ALPHABET
OF LINES
• The basis of all drawings is lines.
• Many different lines are used even in
sample drawings.
• All lines should be made so clearly that
there will be no doubt of their meaning
when the drawing is read.

6. Alphabet of Lines
• Border Line Is the heaviest and
darkest line in a drawing.
It surrounds a drawing
and is usually
rectangular in shape.

7. Alphabet of Lines
• Visible Lines Are sometimes called
object lines. These
represent the visible
outline or parts of an
object.

8. Alphabet of Lines
• Hidden or
invisible lines
These lines consist of
small or short dashes
about 3-4 millimeters
long, with gaps in
between that are about
1-2 millimeters wide.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

9. Alphabet of Lines
• Center line It is the lightest line or finest
line in a drawing. It consists of
one long dash and one short
dash alternately drawn. It is
used to indicate the centers of
entire objects and locations of
circular features.

10. Alphabet of Lines
• Projection or
extension lines
Are continuous lines
extending from a view to
show clearly the dimension
limits.

11. Alphabet of Lines
• Dimension
Line
It consists of three parts:
Arrow heads, fine line and
number of measurements.
It is used to indicate the
measurements of an
object.
6.00

12. Alphabet of Lines
• Reference
Line
It is an irregular, fine,
curved line with an
arrowhead at one end. It is
used to label the parts of
an object.

13. Alphabet of Lines
• Leader Line Is a broken line with an
arrowhead at one end. It is
used for indicating the
measurements and name
of a part.

14. Alphabet of Lines
• Limiting line Is used for limiting the
length of an elongated
object, so that it can be
shown without changing
the size of its view.