Gaspar Monge was a French mathematician and revolutionary who lived from 1746 to 1818. He invented descriptive geometry, which is the theoretical basis for technical drawing. During the French Revolution, Monge served as the Minister of the Marine and helped reform the French educational system by founding the École Polytechnique. Descriptive geometry uses projections and planes to represent three-dimensional objects in two dimensions.

1. THE ORTHOGRAPHIC SYSTEM

2. (1746 –1818) WAS
GASPAR MONGE A FRENCH
MATHEMATICIAN, A
REVOLUTIONARY, AND
THE INVENTOR OF
DESCRIPTIVE GEOMETRY,
THE THEORETICAL BASIS
ON WHICH TECHNICAL
DRAWING IS BASED.
DURING THE FRENCH
REVOLUTION HE SERVED
AS A MINISTER OF THE
MARINE AND WAS
INVOLVED IN THE
REFORMATION OF THE
FRENCH EDUCATIONAL
SYSTEM, FOUNDING
THE ÉCOLE
POLYTECHNIQUE.

3. FIRST
SECOND
QUADRANT
QUADRANT
VERTICAL
PLANE
HORIZONTAL
PLANE
GROUND LINE
FOURTH
THIRD
QUADRANT
QUADRANT

4. REPRESENTATION
OF AN OBJECT
VERTICAL
PROJECTION OBSERVER
HORIZONTAL
PROJECTION

6. A´
A

7. a´#
a´ A
a´ a
a

8. a´#
LEVEL
a´ DISTANCE A OR
LEVEL
HEIGHT
LEVEL OR
OR HEIGHT
HEIGHT DISTANCE
a´ a
DISTANCE
a

9. nts and straight lines
stem.
yed in Technical
chnical Drawing
ed about the
e instruments.
ey are drawing.
s:
e the task.
instruments.
graphic system.
e accurate, neat
uation criteria.)

10. A’ A
A’
A’ A
A

11. B’ B
B’ B’
B
B

12. C’ C
C’
C’
C
C

13. D’ D
D’
D’ D
D

14. E’ E E
E’ E
E

15. F’ F
F’ F

16. A’
D’
C’
B’
D E’ F’
F
A
C
E
B

17. R’
R
V’
R’ V
R
R
H’
H

18. V’
R’
H’ V
R
V’
H
R’ V
R
R
H’
H

19. R’
R
R
R’
V’
R
V

20. V’ R’
V
R
R
R’
V’
R
V

21. R’
R
R
R’
R
H’ H

22. R’
H’
R
H
R
R’
R
H’ H

23. 5.2 Drawing different types of straight line
Object
• To dra
quadra
• To use
Materi
• Graphi
• 45º and
• Ruler a
Presen
• This ac
• The ta
Studen
• The stu
proced
handlin
Evalua
Assess usi
1. Correc
2. Proper
3. Accura
4. Turned
(See Te