IT IS VERY USEFUL FOR THOSE WHO ARE IN SEARCH OF PROBLEMS ON PROJECTION OF LINES. THESE SLIDES ARE VERY USEFUL FOR 1ST YEAR ENGINEERNG FOR SUBJECT ENGINEERING GRAPHICS-I .

2. STRAIGHT LINE
• Definition: Straight line is the Locus of a point, which
moves linearly.
**OR**
Straight line is also the shortest distance between any
two given points.
• Following three positions of staight line in space is
classified as:
1. Line perpendicular to (or in) one reference plane &
hence parallel to both the other planes:
1. Line perpendicular to P.P. & (hence) parallel to both
H.P. & V.P.
2. Line perpendicular to V.P. & (hence) parallel to both
H.P. & P.P.
3. Line perpendicular to H.P. & (hence) parallel to both
V.P. & P.P.

3. 2. Line parallel to (or in) one reference plane
& inclined to other two planes:
(1)Line parallel to ( or in) V.P. & inclined to
H.P. by .
(2) Line parallel to ( or in) H.P. & inclined to
V.P. by .
(3) Line parallel to ( or in) P.P. & inclined to
H.P. by  & V.P. by .
3. Line inclined to all three reference planes
(Oblique lines):
Line inclined to H.P. by , to V.P. by  and
also inclined to profile plane.

4. .

5. b'
a'
a'' b''
F.V.=T.L.
S.V.
10
Y1
Y1
75
..a
.
T.V.=T.L.
Data given :-
•T.L. = 50mm
•Distance:
 above H.P.= 30 mm
in front of V.P.= 10mm
 Line is 10 mm left to
PP.
b

6. Data given :-
•T.L. = 60mm
•Distance:
A above H.P.= 10 mm
in front of V.P.= 30mm
 Plan is seen as a point
b'
a' a''
F.V.=T.L.=60 S.V.
a , b
Y1
Y1
X1
X1
b''
T.V.

7. Data given :-
•T.L. = 50mm
•Distance:
Line above H.P.= 25 mm
A in front of V.P.= 10mm
 Elevation is seen as a
point
a'b' 10 a''
S.V.
b
Y1
Y1
X1
X1
b''
a
T.V.
F.V.

8. 1. PROJECTION OF LINE PARALLEL TO V.P., INCLINED
TO H.P. & P.P.
2. PROJECTION OF LINE PARALLEL TO H.P., INCLINED
TO V.P. & P.P.
3. PROJECTION OF LINE PARALLEL TO P.P., INCLINED
TO H.P. & V.P.

9. 450
Data given :-
•T.L. = 70mm
•Distance:
A on H.P.
A in front of V.P.= 30mm
Line is parallel to
VP and inclined
at 450 to the HP. b
a''
T.V.
b'
a
a'
50
S.V.
b''
X1 X1
Y1
Y1

10. 450
Data given :-
•T.L. = 70mm
•Distance:
A on V.P.
A above H.P. =30mm
Line is parallel to
HP and inclined
at 450 to the VP.
b
a
F.V.
X1
X1
Y1
Y1
T.V.
49.5
a' b' b''
a''
S.V.
49.5

11. X Y
VT’
v
10
20
Locus of a & a1’
 (300)
(450)
a1’
b1’
b1
a1
b’
a’
b
a
FV
TV
HT
h’
Line inclined to all three reference planes (Oblique lines):
300 450

12. a’
b’
30
45
10
LOCUS OF b’ & b’1
X Y
450
VT’
v
HT
h’
LOCUS OF b & b1
100
a
b
b’1


b1
450