**ISOMETRIC AND PERSPECTIVE PROJECTIONS**

**1.The angle between the isometric axes is**

a) 180 degrees

b) 60 degrees

c) 90 degrees

d) 120 degrees**Answer: d**Isometric projection is a type of

Explanation:

projection in which the three dimensions of a

solid are not only shown in one view but also

their actual sizes can be measured directly

from it. So it is needed that there exist equal

angle between the axes for easy measurement

so 360/3=120 degrees is chosen.

**2.The value of the ratio of isometric length to**

true length is

a) 0.141

b) 0.372

c) 0.815

d) 0.642**Answer: c**If we represent a cube in

Explanation:

isometric view the diagonal of upper face of

cube is equal to the true length of the

diagonal. From it by drawing an actual square

around it and then calculating it gives (1/cos

30)/ (1/cos 45) =isometric /true =0.815.**3.The length in isometric drawing of line is**

20 cm. What is the true length of it?

a) 24.53 cm

b) 15.46 cm

c) 19.31 cm

d) 23.09 cm**Answer: a**The ratio of isometric length to

Explanation:

true length is 0.815 so here it is given

isometric length of 20 cm. 0.815 = 20 cm /

true length => true length = 20 cm /0.815 =

24.53 cm. Every time the true length is more

than isometric length.**4.The true length of edge of cube is 15 cm**

what will be the isometric length?

a) 17.78 cm

b) 14.48 cm

c) 12.99 cm

d) 12.22 cm**Answer: d**The ratio of isometric length to

Explanation:

true length is 0.815 so here it is given true

length of 15 cm. 0.815 = isometric length / 15

cm => isometric length = 15 cm x 0.815 =

12.22 cm. Every time the true length is more

than isometric length.**5.The lines parallel to isometric axes are**

called lines.

a) parallel

b) auxiliary

c) isometric

d) oblique**Answer: c**The angle between the

Explanation:

isometric axes is 120 degrees if any line is

parallel to it then those are called isometric

lines. Auxiliary lines may make any angle

with horizontal and oblique is not related

here.**6.The planes parallel to any of the two**

isometric lines are called planes.

a) parallel

b) auxiliary

c) isometric

d) oblique**Answer: c**The planes on which the faces

Explanation:

of cube lie if it is placed in isometric view can

be consider as the isometric planes which are

parallel to two axes of isometric view which

are x, y, z axes of isometric view.**7.Isometric view of cube is drawn the angle**

between the edge of cube and horizontal will

be

a) 15 degrees

b) 120 degrees

c) 45 degrees

d) 30 degrees**Answer: d**Isometric view of cube is

Explanation:

drawn the angle between the edge of cube and

horizontal will be 30 degrees because as the

angle between the base and axis lower to will

be 90 degrees the angle between the axes is

120 degrees. 120-90 = 60 degrees.

**8.Isometric view of cube is drawn the angle**

between the edge of cube and vertical will

be

a) 15 degrees

b) 120 degrees

c) 60 degrees

d) 30 degrees**Answer: cExplanation:** Isometric view of cube is

drawn the angle between the edge of cube and

vertical will be 60 degrees because the angle

between the edge and horizontal is 30 and so

angle between vertical and horizontal is 90.

90 – 30 = 60 degrees.

**9.The true length of line is 40 cm and**

isometric view of it is drawn the length would

decrease to

a) 28.28 cm

b) 32.6 cm

c) 34.6 c

d) 38.63 cm**Answer: b**The ratio of isometric length to

Explanation:

true length is 0.815 so here it is given true

length of 40 cm. 0.815 = isometric length / 40

cm => isometric length = 40 cm x 0.815 =

32.6 cm. Every time the true length is more

than isometric length.**10.The true length of the line is 30 cm and**

isometric view is drawn. How much length is

reduced?

a) 24.45 cm

b) 25.98 cm

c) 4.01 cm

d) 5.55 cm**Answer: d**The ratio of isometric length to

Explanation:

true length is 0.815 so here it is given true

length of 30 cm. 0.815 = isometric length / 30

cm => isometric length = 30 cm x 0.815 =

24.45 cm. 30 cm – 24.45 cm =5.55 cm.**11.The objects we see in nature will be in**

Isometric view.

a) True

b) False**Answer: b**The objects we watch in our

Explanation:

surrounds are not isometric view they are

perspective view. Isometric view is imaginary

view in which lines of sight are perpendicular

to picture plane and are parallel to each other.**12.Isometric view of cube is drawn the angle**

between the adjacent edges is

a) 90 degrees, 120 degrees

b) 60 degrees, 120 degrees

c) 120 degrees, 120 degrees

d) 90 degrees, 30 degrees**Answer: b**Given is a cube in which the

Explanation:

adjacent angle are all equal and equal to 90

degrees and if isometric view is drawn then it

show front faces with angles bet between

them as 120 degrees and if take angles

between the back and front faces we get the

60 degrees.**13.Isometric view of cube is drawn and faces**

of cube are seen as

a) square

b) rectangle

c) rhombus

d) parallelogram**Answer: c**It is given isometric view of

Explanation:

cube is drawn and it shows regular hexagon

in which any of the faces represent rhombus

which have diagonals cutting each other at 90

degrees any other adjacent edges have angles

between them as 60 and 120 degrees.

**ISOMETRIC DRAWINGS**

**1.If isometric projection of an object is**

drawn with true lengths the shape would be

same and size is how much larger than actual

isometric projection?

a) 25%

b) 29.5%

c) 22.5%

d) 33.3%**Answer: cExplanation:** If the foreshortening of the

isometric lines in an isometric projection is

disregarded and instead, the true lengths are

marked, the view obtained will be exactly of

the same shape but larger in proportion than

that obtained by the use of the isometric

scale.

**2.If an isometric projection is drawn with**

true measurements but not with isometric

scale then the drawings are called

a) Isometric projection

b) Isometric view

c) Isometric perception

d) Orthographic view**Answer: b**Due to the ease of construction

Explanation:

and the advantage of measuring the

dimensions directly from the drawing, it has

become a general practice to use the true

scale instead of the isometric scale.**3.If an isometric drawing is made use of**

isometric scale then the drawings are called

a) Isometric projection

b) Isometric view

c) Isometric perception

d) Orthographic view**Answer: a**To avoid confusion, the view

Explanation:

drawn with the true scale is called isometric

drawing or isometric view, while that drawn

with the use of isometric scale is called

isometric projection.

**4.Identify the front view of the below**

isometric view.

**Answer: aExplanation: **Here the isometric view of

some example picture is given. Arrow in

question represents the line of sight in case of

front view from that we can get other views.

Front view is asked which can be watched

along the arrow.

**5.Identify the top view of below isometric**

view.

**Answer: dExplanation:** Here the isometric view of

some example picture is given. Arrow in

question represents the line of sight in case of

front view from that we can get other views.

Top view is asked so considering the arrow

we can find top view.

**6.Identify the side view of the below**

isometric view.

**Answer: bExplanation: **Here the isometric view of

some example picture is given. Arrow in

question represents the line of sight in case of

front view from that we can get other views.

Side is watched from left side or right side of

arrow placed.

**7.Identify the side view of the below**

isometric view.

**Answer: cExplanation: **Here the isometric view of

some example picture is given. Arrow in

question represents the line of sight in case of

front view from that we can get other view.

Side is watched from left side or right side of

arrow placed.

**ISOMETRIC DRAWING OF PLANES OR PLANE FIGURES**

**1.Front view of the square is given and has to**

draw its isometric view which angle the base

has to make with horizontal?

a) 90 degrees

b) 15 degrees

c) 30 degrees

d) 60 degrees**Answer: c**While drawing the isometric

Explanation:

view of any figure made of lines the base

always makes 30 degrees with horizontal and

so in square and another parallel line also

makes 30 degrees with horizontal and other

sides will be perpendicular to horizontal.**2.Front view of the square is given and has to**

draw its isometric view which angle the

vertical edge has to make with horizontal?

a) 90 degrees

b) 15 degrees

c) 30 degrees

d) 60 degrees**Answer: a**In isometric view vertical lines

Explanation:

exist and make 90 degrees with the horizontal

so if the front view of a square is given and

drawn to isometric view the angle between

the vertical edge and horizontal is 90 degrees.**3.Top view of a square is given and has to**

draw its isometric view which angle the base

has to make with horizontal?

a) 90 degrees

b) 15 degrees

c) 30 degrees

d) 60 degrees**Answer: c**While drawing the isometric

Explanation:

view of any figure made of lines the base

always makes 30 degrees with horizontal and

so in square and another parallel line also

makes 30 degrees with horizontal and other

sides will be perpendicular to horizontal.**4.Top view of a square is given and has to**

draw its isometric view which angle the

vertical edge has to make with horizontal?

a) 90 degrees

b) 15 degrees

c) 30 degrees

d) 60 degrees**Answer: c**In isometric view vertical lines

Explanation:

exist and make 90 degrees with the horizontal

so if the top view of a square is given and

drawn to isometric view the angle between

the vertical edge and horizontal is 90 degrees.

**ISOMETRIC DRAWING OF PRISMS AND PYRAMIDS**

**1.Identify the front view from the isometric**

view for the below given pyramid.

**Answer: bExplanation: **The isometric view should be

drawn according to the given views and in

such a way that maximum possible details are

visible. Arrow mark in the given figure show

the direction in which front is taking and

dotted lines represent hidden edges and lines.

**TYPES OF PERSPECTIVE**

**1.When an object has its one or more faces**

parallel to the picture plane, its perspective is

called perspective also called

one point perspective.

a) parallel

b) oblique

c) vanishing

d) angular**Answer: a**When an object has its one or

Explanation:

more faces parallel to the picture plane, its

perspective is called parallel perspective also

called one point perspective as the edges

converge to a single vanishing point of the

parallel faces.**2.When an object has its two faces inclined**

to the picture plane, its perspective is called

perspective also called two point

perspectives.

a) parallel

b) oblique

c) vanishing

d) angular**Answer: d**When an object has its two

Explanation:

faces inclined to the picture plane, its

perspective is called angular perspective also

called two point perspectives as the edges of

the object converge to two vanishing points.**3.When an object has its three faces inclined**

to the picture plane, its perspective is called

perspective also called 3 point perspective.

a) parallel

b) oblique

c) vanishing

d) angular**Answer: b**When an object has its three

Explanation:

faces inclined to the picture plane, its

perspective is called oblique perspective also

called 3 point perspective as edges of the

object converge to three vanishing points.**4.Vanishing points for all horizontal lines are**

inclined at 45 degrees to the picture plane are

given special name of points.

a) vanishing

b) far

c) distance

d) distant**Answer: c**Vanishing points for all

Explanation:

horizontal lines are inclined at 45 degrees to

the picture plane are given special name of

distance points on account of their definite

positions. They are equidistant from the

center of vision.**5.Which are equidistant from the center of**

vision?

a) Station point

b) Ground point

c) Distance point

d) Vanishing point**Answer: c**The distance points are

Explanation:

equidistant from the center of vision the

distance of each from the centre of vision

being equal to the distance of the station point

from the picture plane the perspectives of all

horizontal lines inclined at 45 degrees to the

picture plane converge to a distance points on

the horizon line.**6.The distance of which points from the**

centre of vision being equal to the distance of

the station point from the picture plane?

a) Station point

b) Ground point

c) Distance point

d) Vanishing point

**Answer: cExplanation: **The distance points are

equidistant from the center of vision the

distance of each from the centre of vision

being equal to the distance of the station point

from the picture plane the perspectives of all

horizontal lines inclined at 45 degrees to the

picture plane converge to a distance points on

the horizon line.

**7.The perspectives of all horizontal lines**

inclined at 45 degrees to the picture plane

converge to a points on the horizon

line.

a) vanishing

b) far

c) distance

d) distant**Answer: c**The distance points are

Explanation:

equidistant from the center of vision the

distance of each from the centre of vision

being equal to the distance of the station point

from the picture plane the perspectives of all

horizontal lines inclined at 45 degrees to the

picture plane converge to a distance points on

the horizon line.

**8.The perspective will show the object**

in size when it is placed behind

the picture plane. If the object is moved

nearer the picture plane the size of the

perspective will

a) reduced, decrease

b) reduced, increase

c) increased, reduce

d) increased, increase**Answer: b**The perspective will show the

Explanation:

object reduced in size when it is placed

behind the picture plane. If the object is

moved nearer the picture plane the size of the

perspective will increase and vice versa.

**9.The perspective will show the object in size when it is placed in front of the picture plane. If the object is moved nearer the picture plane the size of the perspective will, **

a) reduced, decrease

b) reduced, increase

c) increased, reduce

d) increased, increase**Answer: cExplanation: **The perspective will show the

object increased in size when it is placed in

front of the picture plane. If the object is

moved nearer the picture plane the size of the

perspective will reduce and vice versa.