Graphics
Question 1 
In 3D Graphics, which of the following statements about perspective and parallel projection is/are true?

P: In a perspective projection, the farthest an object is from the center of projection, the smaller it appears.
Q: Parallel projection is equivalent to a perspective projection where the viewer is standing infinitely far away
R: Perspective projections do not preserve straight lines.
Choose the correct answer from the code given below:
Code:P and R only  
P, Q and R  
Q and R only  
P and Q only

Question 1 Explanation:
Perspective Projection :
Perspective projection is representing or drawing objects which resemble the real thing.
Perspective projection preserves the straight line.
In perspective projection, objects that are far away appear smaller, and objects that are near appear bigger.
Parallel lines do not remain parallel.
Distance and angles are not preserved.
Parallel Projection :
In this projection drawing objects looks less realistic.
In this projection parallel lines remains parallel.
Angles are not preserved in this projection.
It is good for exact measurements.
Perspective projection is representing or drawing objects which resemble the real thing.
Perspective projection preserves the straight line.
In perspective projection, objects that are far away appear smaller, and objects that are near appear bigger.
Parallel lines do not remain parallel.
Distance and angles are not preserved.
Parallel Projection :
In this projection drawing objects looks less realistic.
In this projection parallel lines remains parallel.
Angles are not preserved in this projection.
It is good for exact measurements.
Question 2 
In 3D Graphics, which of the following statement/s is/are true ?

P: Backface culling is an example of an imageprecision visiblesurface determination.
Q: ZBuffer is a 16bit, 32bit, or 64bit field associated with each pixel in a frame buffer
that can be used to determine the visible surface at each pixel.
Choose the correct answer from the code given below :;
Code :P only  
Q only
 
Neither P nor Q
 
P and Q

Question 2 Explanation:
Back Face Culling:
→ Backface culling (an object space algorithm) works on 'solid' objects which you are looking at from the outside. That is, the polygons of the surface of the object completely enclose the object.
→ Backface culling is not an example of an imageprecision visiblesurface determination.
→ Backface culling can very quickly remove unnecessary polygons. Unfortunately there are often times when backface culling can not be used. For example if you wish to make an opentopped box  the inside and the outside of the box both need to be visible, so either two sets of polygons must be generated, one set facing out and another facing in, or backface culling must be turned off to draw that object.
1. Back faces: faces of opaque object which are “pointing away” from viewer.
2. Back face culling – remove back faces (supported by OpenGL).
→ TRUE: ZBuffer is a 16bit, 32bit, or 64bit field associated with each pixel in a frame buffer that can be used to determine the visible surface at each pixel.
→ Backface culling (an object space algorithm) works on 'solid' objects which you are looking at from the outside. That is, the polygons of the surface of the object completely enclose the object.
→ Backface culling is not an example of an imageprecision visiblesurface determination.
→ Backface culling can very quickly remove unnecessary polygons. Unfortunately there are often times when backface culling can not be used. For example if you wish to make an opentopped box  the inside and the outside of the box both need to be visible, so either two sets of polygons must be generated, one set facing out and another facing in, or backface culling must be turned off to draw that object.
1. Back faces: faces of opaque object which are “pointing away” from viewer.
2. Back face culling – remove back faces (supported by OpenGL).
→ TRUE: ZBuffer is a 16bit, 32bit, or 64bit field associated with each pixel in a frame buffer that can be used to determine the visible surface at each pixel.
Question 3 
How much memory is required to implement the zbuffer algorithm for a 512 x 512 x 24 bitplane image?
768 KB  
1 MB  
1.5 MB  
2 MB 
Question 3 Explanation:
In computer graphics, zbuffering, also known as depth buffering, is the management of image depth coordinates in 3D graphics, usually done in hardware, sometimes in software
In a 3drendering engine, when an object is projected on the screen, the depth (zvalue) of a generated pixel in the projected screen image is stored in a buffer (the zbuffer or depth buffer).
A zvalue is the measure of the perpendicular distance from a pixel on the projection plane to its corresponding 3dcoordinate on a polygon in worldspace.
Zbuffer requires 2 type of buffers to be filled: Depth buffer and Frame buffer
The amount of memory required by depth buffer in terms of bits is 512 x 512 x 24 = 6291456
The amount of memory required by frame buffer in terms of bits is 512 x 512 x 24 = 6291456
Total memory is required is sum of both depth and frame buffer memories = 6291456 + 6291456 = 12582912 bits which is equivalent to 1.5 MB(1.5x1024x1024x8)
In a 3drendering engine, when an object is projected on the screen, the depth (zvalue) of a generated pixel in the projected screen image is stored in a buffer (the zbuffer or depth buffer).
A zvalue is the measure of the perpendicular distance from a pixel on the projection plane to its corresponding 3dcoordinate on a polygon in worldspace.
Zbuffer requires 2 type of buffers to be filled: Depth buffer and Frame buffer
The amount of memory required by depth buffer in terms of bits is 512 x 512 x 24 = 6291456
The amount of memory required by frame buffer in terms of bits is 512 x 512 x 24 = 6291456
Total memory is required is sum of both depth and frame buffer memories = 6291456 + 6291456 = 12582912 bits which is equivalent to 1.5 MB(1.5x1024x1024x8)
Question 4 
In graphics, the number of vanishing points depends on
the number of axes cut by the projection plane  
the centre of projection  
the number of axes which are parallel to the projection plane  
the perspective projections of any set of parallel lines that are not parallel to the projection plane 
Question 4 Explanation:
→Projections of lines that are not parallel to the view plane (i.e. lines that are not perpendicular to the view plane normal) appear to meet at some point on the view plane.
→This point is called the vanishing point. A vanishing point corresponds to every set of parallel lines.
→This point is called the vanishing point. A vanishing point corresponds to every set of parallel lines.
Question 5 
Which of the following is true about the zbuffer algorithm?
It is a depth sort algorithm  
No limitation on total number of objects  
Comparisons of objects is done  
zbuffer is initialized to background colour at start of algorithm 
Question 5 Explanation:
The Zbuffer algorithm is a convenient algorithm for rendering images properly according to depth.
To begin with, a buffer containing the closest depth at each pixel location is created parallel to the image buffer. Each location in this depth buffer is initialized to negative infinity.
Since the algorithm processes objects one at a time, the total number of polygons in a picture can be arbitrarily large.
To begin with, a buffer containing the closest depth at each pixel location is created parallel to the image buffer. Each location in this depth buffer is initialized to negative infinity.
Since the algorithm processes objects one at a time, the total number of polygons in a picture can be arbitrarily large.
Question 6 
A system is having 8 M bytes of video memory for bitmapped graphics with 64bit colour. What is the maximum resolution it can support?
800 x 600  
1024 x 768  
1280 x 1024  
1920 x 1440 
Question 6 Explanation:
Explanation:
Given file size is 8M bytes= 8*1024**1024*8=83,88,608
From the options,
⦁ 800*600*8=34,80,000
⦁ 1024*768*8=62,91,456
⦁ 1280*1024*8=13,10,720
⦁ 1920*1440*8=22,118,400
From the above , option A and B are less than file size.
From that two , maximum one is option B.
Given file size is 8M bytes= 8*1024**1024*8=83,88,608
From the options,
⦁ 800*600*8=34,80,000
⦁ 1024*768*8=62,91,456
⦁ 1280*1024*8=13,10,720
⦁ 1920*1440*8=22,118,400
From the above , option A and B are less than file size.
From that two , maximum one is option B.
Question 7 
The term Phong associated with
Ray tracing  
shading  
Hidden line removal  
a game 
Question 7 Explanation:
Phong shading is a perfragment color computation. The vertex shader provides the normal and position data as out variables to the fragment shader. The fragment shader then interpolates these variables and computes the color
Question 8 
A Steiner patch is
Biquadratic Bezier patch  
Bicubic patch  
Circular patch only  
Bilinear Bezier patch 
Question 8 Explanation:
Steiner patches are triangular surface patches for which the Cartesian coordinates of points on the patch are defined parametrically by quadratic polynomial functions of two variables. So these surfaces are formed from biquadratic Bezier patches.
Question 9 
The process of rotating the image by 1800 without changing its size is called:
Translation  
Rotation  
Scaling  
Reflection 
Question 9 Explanation:
The process of rotating the image by 1800 without changing its size is called Rotation
There are 9 questions to complete.