Computer Graphics · Unit 7
3D Graphics and Projections
Exam-focused notes for 3D Graphics and Projections (Computer Graphics, BIT304): what the TU syllabus asks and how it has actually been tested, with 5 solved past questions from this unit.
What this unit covers
- 3D coordinate systems
- Parallel projection
- Perspective projection
- Projection coordinate calculations
- Wireframe representation of 3D objects
- 3D object representations and storage
3D object representations and storage
How the geometric and attribute information of a 3D objects are stored for the object representations? Explain with suitable example. [5]
3D objects are represented in computer graphics by storing two fundamental types of information: 1. Geometric Information - shape and spatial structure 2. Attribute Information - visual and material properties --- Geometric data defines the shape and positi...
Full solved answer →Parallel projection
Differentiate between parallel and perspective projection. Perform the rotation of triangle with vertices A(5,7), B(12,85) and C(5,3) counterclockwise 30 degree about the pivot point (5,3).[10]
Aspect Parallel Projection Perspective Projection --------- Projectors Projection lines (projectors) are parallel to each other Projectors converge to a single point (center of projection) Center of projection At infinity At a finite distance Vanishing poin...
Full solved answer →Differentiate between parallel and perspective projection. [5]
Definition: Parallel projection is a projection technique where all projection lines are parallel to each other and perpendicular (or at a fixed angle) to the projection plane. Key Characteristics: - Projection lines remain parallel throughout - No vanishin...
Full solved answer →Wireframe representation of 3D objects
Explain the wireframe representation of 3D objects. [5]
Wireframe representation is a method of displaying 3D objects using only edges and vertices, without rendering surfaces or faces. The object appears as a skeleton made of lines connecting corner points in 3D space. 1. Structure - Consists of vertices (corne...
Full solved answer →Projection coordinate calculations
Obtain perspective projection co-ordinates for the pyramid with vertices of base (15, 15, 10), (20, 20, 10), (25, 15, 10), (20, 10, 10) and apex (20, 15, 2), given that Zprp = 20 and Zvp = 0.[10]
- Base vertices: - $V1(15, 15, 10)$ - $V2(20, 20, 10)$ - $V3(25, 15, 10)$ - $V4(20, 10, 10)$ - Apex: $V5(20, 15, 2)$ - Center of projection: $Z{prp} = 20$ - View plane: $Z{vp} = 0$ For a center of projection on the z-axis at $z = Z{prp}$ and view plane at $...
Full solved answer →Make Unit 7 stick
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