Q.1 Which of the following is the most common representation of 3D objects in computer graphics?
Vector fields
Polygonal meshes
Bezier curves
Raster images
Explanation - Polygonal meshes are widely used because they balance simplicity and efficiency for rendering 3D objects.
Correct answer is: Polygonal meshes
Q.2 In a polygon mesh, what is the smallest unit that defines the surface?
Line segment
Triangle
Cube
Vertex shader
Explanation - Triangles are the simplest polygon used in 3D graphics since they are always planar and easy to process.
Correct answer is: Triangle
Q.3 What does 'vertex' represent in 3D modeling?
A surface normal
A point in 3D space
A texture unit
A frame of animation
Explanation - A vertex is a point in 3D space that defines the corners of polygons in a mesh.
Correct answer is: A point in 3D space
Q.4 Which coordinate system is most commonly used in 3D graphics?
Polar coordinates
Spherical coordinates
Cartesian coordinates
Barycentric coordinates
Explanation - 3D graphics generally use Cartesian coordinates (x, y, z) for representing points in space.
Correct answer is: Cartesian coordinates
Q.5 What is the main advantage of using NURBS surfaces in 3D modeling?
They are easier to animate
They allow smooth curved surfaces
They require no computation
They replace textures
Explanation - NURBS surfaces provide mathematical precision for smooth curves and surfaces in 3D graphics.
Correct answer is: They allow smooth curved surfaces
Q.6 Which file format is commonly used to store 3D object models?
JPEG
OBJ
MP3
TXT
Explanation - The OBJ format is widely used for representing 3D geometry as meshes.
Correct answer is: OBJ
Q.7 In a 3D model, what does an 'edge' represent?
A line connecting two vertices
A triangle face
A texture seam
A lighting vector
Explanation - An edge is the line segment that connects two vertices in a mesh.
Correct answer is: A line connecting two vertices
Q.8 Which 3D modeling technique involves manipulating points in a lattice structure?
Polygonal modeling
NURBS modeling
Subdivision surfaces
Lattice deformation
Explanation - Lattice deformation uses a grid-like structure to deform a 3D model smoothly.
Correct answer is: Lattice deformation
Q.9 What is the role of UV mapping in 3D modeling?
Defining motion paths
Projecting textures onto 3D models
Generating vertex normals
Controlling light reflections
Explanation - UV mapping maps 2D textures onto the surface of a 3D model.
Correct answer is: Projecting textures onto 3D models
Q.10 Which term refers to the process of increasing polygon detail for smoother surfaces?
Extrusion
Subdivision
Decimation
Boolean operation
Explanation - Subdivision smooths a model by dividing polygons into smaller ones.
Correct answer is: Subdivision
Q.11 What is the 'normal vector' of a polygon used for?
Coloring faces
Determining face orientation
Assigning textures
Controlling animation speed
Explanation - Normal vectors define the direction a surface is facing, crucial for lighting calculations.
Correct answer is: Determining face orientation
Q.12 Which of these is NOT a solid modeling method?
Constructive Solid Geometry (CSG)
Boundary Representation (B-Rep)
Voxel modeling
Phong shading
Explanation - Phong shading is a lighting technique, not a solid modeling method.
Correct answer is: Phong shading
Q.13 In 3D graphics, voxels are most similar to which 2D concept?
Pixel
Line
Polygon
Curve
Explanation - Voxels are 3D equivalents of pixels, representing values in 3D space.
Correct answer is: Pixel
Q.14 Which operation combines two 3D objects by adding their volumes?
Intersection
Difference
Union
Subdivision
Explanation - In Constructive Solid Geometry, a union merges the volumes of two objects.
Correct answer is: Union
Q.15 What is the advantage of wireframe representation in 3D graphics?
More realistic rendering
Faster computation
Automatic texturing
Better shading
Explanation - Wireframe models are simpler and render quickly since they only display edges and vertices.
Correct answer is: Faster computation
Q.16 Which algorithm is used to remove hidden surfaces in 3D rendering?
Bresenham’s algorithm
Z-buffering
Flood fill
Dijkstra’s algorithm
Explanation - Z-buffering keeps track of depth values to remove hidden surfaces.
Correct answer is: Z-buffering
Q.17 Which 3D primitive is most commonly used in CAD applications?
Sphere
Box
Extrusion
Torus
Explanation - Extrusion is used extensively in CAD to extend 2D shapes into 3D models.
Correct answer is: Extrusion
Q.18 Which type of 3D transformation changes the size of an object?
Translation
Rotation
Scaling
Reflection
Explanation - Scaling transformations increase or decrease the size of a model.
Correct answer is: Scaling
Q.19 What is the process of reducing polygon count in a mesh called?
Decimation
Subdivision
Extrusion
Tessellation
Explanation - Decimation reduces the number of polygons while retaining shape details.
Correct answer is: Decimation
Q.20 In homogeneous coordinates, which additional component is added to 3D points?
w
h
t
d
Explanation - Homogeneous coordinates add a fourth component 'w' for efficient matrix transformations.
Correct answer is: w
Q.21 Which of the following is NOT a geometric transformation?
Translation
Rotation
Scaling
Shading
Explanation - Shading is a rendering technique, not a transformation.
Correct answer is: Shading
Q.22 What does tessellation in 3D graphics refer to?
Smoothing edges
Dividing surfaces into smaller polygons
Mapping textures
Removing hidden lines
Explanation - Tessellation breaks surfaces into smaller polygons for detailed rendering.
Correct answer is: Dividing surfaces into smaller polygons
Q.23 Which mathematical concept is often used to perform rotations in 3D?
Determinants
Quaternions
Eigenvalues
Fourier series
Explanation - Quaternions are used for smooth and gimbal-lock-free 3D rotations.
Correct answer is: Quaternions
Q.24 Which projection preserves parallel lines but does not represent depth accurately?
Perspective projection
Orthographic projection
Isometric projection
Cylindrical projection
Explanation - Orthographic projection preserves sizes and parallelism but lacks depth perception.
Correct answer is: Orthographic projection
Q.25 Which component of a 3D pipeline converts 3D objects into 2D images?
Geometry processing
Rasterization
Clipping
Shading
Explanation - Rasterization transforms vector-based 3D geometry into pixel data for display.
Correct answer is: Rasterization