1. Which of the following formula is used for converting world coordinates to the viewing coordinates?
a) M WC, VC = R z x R y x R z x T
b) M WC, VC = R x ⋅ R y ⋅ R z ⋅T
c) M WC, VC = R z ⋅ R y ⋅ R z ⋅Tx . Ty. Tz
d) M WC, VC = R z ⋅ R y ⋅ R z ⋅T
Explanation: The formula that is used for converting world coordinates to the viewing coordinates is – M WC, VC = R x ⋅ R y ⋅ R z ⋅T
It is the dot product of the rotation vectors done in x, y and z direction as well as the translation vector that is used to convert the world coordinates to the viewing coordinates.
2. Which of the following is defined as mapping of a point P(x, y, z) onto its image P’(x’, y’, z’) in the projection plane?
a) Mapping
b) Transformation
c) Clipping
d) Projection
Explanation: Projection is defined as mapping of a point P(x, y, z) onto its image P’(x’, y’, z’) in the projection plane. Projection can be divided into two broad categories – parallel projection and perspective projection.
3. The planar geometric projections can be divided into how many categories?
a) 2
b) 3
c) 4
d) 5
Explanation: The planar projections can be divided into 2 broad categories. These are Parallel Projection and Perspective Projection.
4. The Parallel Projection can be divided into how many categories?
a) 6
b) 8
c) 2
d) 5
Explanation: Parallel Projection can be mainly divided into two parts – Orthographic Projection and Oblique Projection. Orthographic projection can be further divided into – Top, Front, Side and Axonometric. Oblique Projection can be further divided into – Cavalier and Cabinet.
5. Which types of lines are used to transform coordinate points to the view plane in parallel projection?
a) Intersecting Lines
b) Parallel Lines
c) Perpendicular Lines
d) Bisecting Lines
Explanation: Coordinate position are transformed to the view plane along parallel lines. A parallel projection preserves relative proportion of objects, but does not give us a realistic representation of the object.
6. Which type of parallel projection has projection vectors perpendicular to the viewing plane?
a) Axonometric Projection
b) Orthographic Projection
c) Oblique Projection
d) Perspective Projection
Explanation: In orthographic projection, the projection vectors are perpendicular to the viewing plane. Orthographic projection is used to produce the front, side, and top views of an object.
7. Which type of parallel projection has projection vectors not perpendicular to the viewing plane?
a) Oblique Projection
b) Perspective Projection
c) Axonometric Projection
d) Cabinet Projection
Explanation: In oblique projection, the projection vectors are not perpendicular to the viewing plane. Angles and lengths are preserved for faces parallel the plane of projection. Preserves 3D nature of an object
8. Which of the following orthographic parallel projection is called as a plan view?
a) Front
b) Side
c) Rear
d) Top
Explanation: Top orthographic projection is called as plan view. Front, rear and side orthographic projections of an object are called as the elevations.
9. The Axonometric parallel projection can be divided into how many sub categories?
a) 2
b) 3
c) 4
d) 5
Explanation: The Axonometric parallel projection can be divided into 3 main subcategories. These are – Isometric parallel projection, Dimetric parallel projection and trimetric parallel projection.
10. Oblique parallel projection preserves the 3 D nature of the object.
a) True
b) False
Explanation: In oblique parallel projection the 3 D nature of the object remains preserved. The angles, distances and the parallel lines in the plane are projected accurately. In oblique projection, projections are not perpendicular to the viewing plane.