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:
Graphics Algorithms: Statement Analysis
This solution analyzes the truthfulness of statements regarding common computer graphics algorithms.
Analyzing Statement A: Painters' Algorithm
The Painters' algorithm sorts polygons based on depth and renders them from furthest to nearest. This process is fundamentally a form of depth sorting. Therefore, the statement 'Painters' algorithm is also called depth sort algorithm' is considered true.
Analyzing Statement B: Gourad Shading Interpolation
Gourad shading calculates illumination at the polygon vertices and then interpolates these vertex colors across the face of the polygon. This process is known as interpolating shading. Thus, the statement 'Gourad shading is on interpolating shading method' is true.
Analyzing Statement C: Gourad Shading Averaging
While Gourad shading involves calculations based on vertex colors, describing it solely as an 'averaging shading method' is less precise than calling it an 'interpolating' method. It interpolates colors derived from vertex lighting calculations. Compared to statement B, this description is less definitive. Therefore, this statement is considered less accurate or potentially false in the context of standard definitions.
Analyzing Statement D: Z-buffer Algorithm Depth
The Z-buffer algorithm (or depth buffer algorithm) works by storing the depth (Z-value) of the closest object rendered so far for each pixel. When rendering a new polygon, if its fragment's depth is *less* (closer) than the stored depth in the Z-buffer, the fragment is drawn, and the Z-buffer is updated. It finds the *smallest* depth value, not the largest. Therefore, the statement 'The Z-buffer algorithm finds the largest depth value Z' is false.
Conclusion on True Statements
Based on the analysis:
- Statement A is true.
- Statement B is true.
- Statement C is less accurate/misleading.
- Statement D is false.
The statements that are definitively true are A and B. Option 1 correctly identifies these.
Important Questions from Three Dimensional Concepts
K-mean clustering algorithm has clustered the given 8 observations into 3 clusters after 1st iteration as follows:
C1 : {(3,3), (5,5), (7,7)}
C2 : {(0,6), (6,0), (3,0)}
C3 : {(8,8),(4,4)}
What will be the Manhattan distance for observation (4,4) from cluster centroid C1 in second iteration?
In the context of 3D computer graphics, which of the following statements is/are TRUE?
P: Orthographic transformations keep parallel lines parallel
Q: Orthographic transformations are affine transformations
Select 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:
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:
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:
