In the context of 3D Computer graphics, which of the following statements is/are correct? (A) Under perspective projection, each set of parallel lines in the object do not stay parallel in the image (except those that are parallel to the viewplane to start with). (B) Applying a perspective transformation in the graphics pipeline to a vertex involves dividing by its 'z' coordinate. (C) Perspective transformation is a linear transformation. Choose the correct answer from the options given below:
(A) and (B) only
In a camera coordinate system with the viewing direction along the z-axis, perspective projection maps \((x,y,z)\) to coordinates proportional to \((x/z,y/z)\). Thus B holds in this standard convention. Parallel lines not parallel to the viewplane generally converge, giving A. The division makes the Cartesian mapping nonlinear, so C is false; a homogeneous matrix representation does not remove the perspective divide.
Important Questions from Three Dimensional Concepts
- A normalized matrix that maps a 3D window specified by coordinates (1, 1, 1) and (4, 5, 6) on to a viewport specified by coordinates (2, 4, 2) and (8, 10, 8) is
Which of the following statements are true.
A. Painters' algorithm is also called depth sort algorithm.
B. Gourad shading is on interpolating shading method.
C. Gourad shading is an averaging shading method.
D. The Z-buffer algorithm finds the largest depth value Z.
Choose the correct answer from the options given below:
- _________ and _________ views cannot be framed together for rendering a computer visual appropriately.
Concerning phong shading and Gouraud shading in a 3D scene, which of the following statements are true ?
(A) Gouraud shading requires more computation than phong shading.
(B) Gouraud shading linearly interpolates the color of an interior pixel from the color at the vertices
(C) Phong shading interpolates over the normal vectors specified at the vertices.
Choose the correct answer from the options given below:
Given below are different properties of 3D projections from A-D. Identify the correct order on the basis of property true of (i) a perspective projection only, (ii) an orthographic projection only, (iii) both orthographic and projective transformations and (iv) neither orthographic nor projective transformation, respectively.
(A) Straight lines are mapped to straight lines.
(B) Distances and angles are (in general) preserved.
(C) Far away objects appear the same size as closer ones
(D) Requires homogeneous coordinates in order for it to be encoded into a linear transformation.
Choose the correct answer from the options given below:
