1. Determining the horizontal and vertical trace of the line
P2’’
1x2 q” q’
Q1’
p’’
Q2”
P1’’
1x2
P2’
Q1”
Q2’
P1’ p’

2. Exercise 1
Construct the orthogonal projection of the straight line q passing through point T, parallel to the plane 1 and intersecting the given straight line p.
p’’ p’
T’’ T’
q’’
S’’ S’
1x2 q’

3. Exercise 2
Construct the orthogonal projection of the straight line p that intersects the line g in the point A(1,-,-) and is parallel to 1 i 2. Straight line g is given with points F(4,1,1) i G(0,3,3). 1
G’’
F’’ F’ G’ A’
A’’
p’’ p’
g’’ g’
1x2

4. Exercise 3
Construct a line segment of length d on a straight line p starting at point T.
p’’
B’’
A’’
d’’ d
T’’
P1’’
P1’ p0
Instructions. True length of a line segment can be determined from a projection of the line only in the line is in a projection plane or parallel to .
Otherwise, if a straight line is in an arbitrary position, for determining the true length it is nessesary to rotate the line into the projection plane. A’ B’
1x2 d’ B0 d T’ T0 d p’ A0

5. Angles of inclination of a straight line to the planes of projection
The line can be rotated using any point incident with it, but it is common to use its horizontal or vertical trace.
P2’’ 2 p0
p’’ A” A’
P10
P1’’
1x2
1= (p,p’)
P2’
P1’
2= (p,p’’) . p’ 1 p0 A0
P20

6. Exercise 4
Let a straight line p be given with points A(2,3,4) i B(5,-1,2). Determine its horizontal, vertical trace and first angle of inclination. p0
P1’ p’ p” A’ A”
P2” B’ B” 1 1
1x2
P’2
P”1 A0