1. University of Warith AL-Anbiya’a
College of Engineering
Air-condition & Refrigeration Department
Desprictive geometry II
First stage
Asst.Lec. Aalaa Mohammed AL-Husseini

2. Plane Setting
1. General position : where the plane doesn't vertical or parallel to each of projections’ levels.
2. Special cases:
Vertical level ( level vertical to horizontal plane of projection):
The projection of this level on horizontal plane of projection coincide on the horizontal traces.
The angle between the horizontal traces and the earth line = Z2 , while the angle with the vertical folding line =Z3 , and Z1=90ᵒ as shown in figure below:

4. 2. The level vertical to face plane of projection:
The projection of this level on face plane of projection coincide on the face traces.
The angle between the face traces and the earth line = Z1 , while the angle with the vertical folding line =Z3 , and Z2=90ᵒ as shown in figure below:

5. 3. The level vertical to side plane of projection:
The projection of this level on side plane of projection coincide on the side traces.
The angle between the side traces and the earth line = Z1 , while the angle with the vertical folding line =Z2 , and Z3=90ᵒ as shown in figure below:

6. 4. The horizontal plane (parallel to horizontal plane of projection) :
The horizontal plane cross the face and side planes of projection by a line vertical to the vertical folding line, so T2 & T3 crossed on the vertical folding line and the angle between them is 90ᵒ. After rotation of the side plane of projection by 90ᵒ in the direction of clockwise , the traces become in the same straightness as shown in the figure below:
The horizontal plane : Z1=0 and Z2=Z3= 90ᵒ

7. 5. The face plane (parallel to face plane of projection) :
In this state the plane will be vertical to the horizontal and side planes of projection.
Z2=0 , Z1=Z3= 90ᵒ
the horizontal projection of the plane coincide on the horizontal traces T1 , and the side projection of the plane coincide on the side traces T3 . The traces shown in the figure below:

8. 6. The side plane (parallel to side plane of projection) :
In this state the plane will be vertical to the horizontal and face planes of projection.
Z3=0 , Z1=Z2= 90ᵒ
the horizontal and face traces ( T1 ,T2) will be on the same straightness after the rotation of the plane.

9. 7. If the plane passes through the earth line so the plane will be vertical to the side plane of projection.

10. 8. If the plane passes through the vertical folding line so the traces will be as shown:

11. 9. If the plane passes through the vertical line between side and horizontal planes of projection , so the traces will be as shown:

12. ABCD a horizontal square where A( 2,1,2.5) B( X, 2.5 , 1)
Example 1:
ABCD a horizontal square where A( 2,1,2.5) B( X, 2.5 , 1)
The required : represent the square.
SOL/ 1. draw A ,A ,B
2. AB horizontal straight line the face projection // the earth line so draw a straight line from A // the earth line.
This line represent the face projection of the straight line AB , at the same time all the face projection of the squares’ points ( as the theory : the projection of the plane shape on plane vertical on it will be straight line .
3. The square ribbons are equally and vertically, the other ribbons will be drawn in the term of AB
4. From the heads of the square in the horizontal projection, draw a vertical projectional lines vertical to the earth line to get the face projection of the points A,B,C,D

14. Example 2:
cubic with horizontal above base ABCD ,where A( 2,1,2.5) B( X, 2.5 , 1)
If this cubic in the first location , draw it’s projection and it’s geometrical center projection.
SOL/ 1. draw A ,A ,B
horizontal base A , B , C ,D , with the aid of A B complete the drawing of the square A B C D .
The face projection of the above base is straight line and the same straightness of A B , stretched on it C D by drawing lines from C D.
The height of the cubic = to the length of one of it’s ribbons. AB= R.L ( the projection of straight line on a parallel plane appear by the real length).
The height of the cubic = the length of A B.
5. The below base is a straight line // the earth line.
6. The horizontal projection of the geometrical center M will be at the center of the square and the face projection at the center of the

15. Line between the above and below bases.

16. Thank you For Your Attention