Questions 1-40 Descriptive Geometry

Front 1

1. What is the first and most important aim of descriptive geometry?

Back 1

1. The main point of descriptive geometry is giving theoretical basis for making sketches and reading them.

Front 2

2. What is the difference between central and orthogonal projection?

Back 2

2. In central projecting projection rays are based from one point. In orthogonal projection projection rays are parallel and they have a common destination.

Front 3

3. What the types of parallel projection and how do these projections differfrom each other?

Back 3

3. Parallel projection divides into two: oblique projection and cross projection.Turing oblique projection projection rays fall to the plane obliquely.Turing cross projection projection rays fall to the screen perpendiculary.

Front 4

4. Why can a one-view drawing not determine an object without anyadditional data?

Back 4

4. Drawing has to determine object. Including it has to determine all geometrical values of object, but only one image does not determine object in the room without any additional data.5. If straight line matches with projected rays.

Front 5

5. In what case a straight line projection is a point?

Back 5

If straight line matches with projected rays.

Front 6

6. In what case a planar object parallel projection is a straight line?

Back 6

?

Front 7

7. What is the distortion factor of a straight line segment?

Back 7

Distortion coefficient shows how many times the lengthof line segment projection lower the true length of theline section.

Front 8

8. In what limits may the distortion factor of a straight line segmentbecome: 1) an orthogonal projection, 2) a parallel projection?

Back 8

1) 0 £ m£ 1 2) 0 £ m £ ¥

Front 9

9. What shape will the circle parallel projection take, if it is: 1) parallel torays 2) parallel to the screen?

Back 9

1) line segment 2) in oblique projection to ellipse, in orthographic projection to circle

Front 10

10.How does the length of a straight line segment orthographic projectionmanifest through the line segment angle and the length of the section?

Back 10

The true length of the clip, and the cosine of the angle of inclination of its multiplying

Front 11

11.What is the inclination angle of a straight line segment?

Back 11

inclination angle is the acute angle between the screen and line segment

Front 12

12.To what limits can the value of an acute angle vary in orthogonalprojection?

Back 12

0 (equal or bigger, losed way to 0) g (equal or bigger, losed way to g) 180

Front 13

13.Express the length of the line segment a, if its length in parallelprojection a' and the distortion factor m are known.

Back 13

a=a’/m

Front 14

14.Formulate a sentence about the right angle orthographic projection.

Back 14

g

Front 15

15.What requirements should drawings meet?

Back 15

Requirements for object projection:simplicity,measurability,pictoriality, visualitysingularity of determination

Front 16

16.List the basic methods of the ways for determining an object.

Back 16

-method of Monge or multiview method;-axonometric projection;-horizontal projection

Front 17

17.What does the concept of "reading the drawing" mean?

Back 17

g

Front 18

18.What are the point-coordinates?

Back 18

g

Front 19

19.What segment of a coordinate corresponds to the frontal/horizontal/lateral quote?

Back 19

Frontal quote is x-axis segment, horizontal quote is y-axis segment, lateral quote is z-axis segment

Front 20

20.What coordinate segment is equal to the side-view of the point distancefrom the z-axis?

Back 20

with horizontal quote, y-axis segment

Front 21

21.What line of a point two-view is referred to as the connection line?

Back 21

g

Front 22

22.Where is located point A, if A ≡ A", and where is located point B, if B ≡ B'?

Back 22

Point A in on the frontal plane, point B is on the ….

Front 23

23.Formulate the main characteristic of a three-view.

Back 23

g

Front 24

24.Draw a three-view of point A(x; y; z).

Back 24

g

Front 25

25.Draw a three-view of point A(x; y; z), if its distance from the horizontalscreen is a, from the frontal screen b and from the side screen - c mm.

Back 25

g

Front 26

26.What is a two-view with no axis?

Back 26

g

Front 27

27.What is the horizontal trace, frontal trace and profile trace of a plane?

Back 27

g

Front 28

28.Derive the traces P(P';P") and E(E';E") of a chosen straight line a.

Back 28

g

Front 29

29.What straight line is called the line of general location?

Back 29

g

Front 30

30.What straight line is called 1) horizontal to screen, 2) frontal to screen? How can it be characterised on the basis of a two-view image?

Back 30

30. – 1-The line is parelell to the horizontal plane, and parelell to the frontal plane, the frontal, and horizontal views are horizontal lines;

2- The line is parelell to the horizontal plane, and perpendicular to the frontal plane, the frontal view is a point, the horizontal view is a vertical line.

Front 31

31.Formulate the terms when a straight line is located on a plane.

Back 31

31 – If the line is located on the plane (the plane contains the line) two of the line’s non-coinciding points are located on the plane.

Front 32

32.What are the true lengths of general position straight line segment righttriangle catets, used to derive true length of general position straight linesegment, equal to?

Back 32

?

Front 33

33.Derive the true length of straight line segment AB, if A(50,0;10) andB(10;20;40).

Back 33

33 – Solution: Workbook, 27a

Front 34

34.What is the straight line inclination angle between the line and thehorizontal plane (between the line and the frontal plane) and how can itbe determined?

Back 34

34 – Solution:Workbook, 27b fi1-line-horizontal plane fi2-line-frontal plane

Front 35

35.Formulate the characteristic of two straight lines being parallel on thetwo-view basis

Back 35

?

Front 36

36.Formulate the characteristic of two straight lines’ intersection on thetwo-view basis

Back 36

?

Front 37

37.Make a two-view sketch of two skew lines (a and b). Solve the shadingissue.

Back 37

Like solition of Workbook 27b, but with two SKEW lines. (shading problem- ?)

Front 38

38.Can two skew lines’ parallel projections be parallel?

Back 38

38 – Yes, they can (two skew edges of a cube, to a projection plane paralell to a face of the cube)

Front 39

39.Can two skew lines parallel projections intersect?

Back 39

39- In general cases they can (In particular case, when one of the lines is perpendicular to the projecting plane – the projection is a point, - no intersection)

Front 40

40.List all the ways for determining a plane.

Back 40

40 – By 3 point in the space-By two intersecting lines-By a line and a point, wich is not ont he line-Two parelell lines-A point, and a line coinciding the point, and being paralell to the plane