Computer Graphics · Unit 7 · 5 hrs
Visible Surface Detections
Exam-focused notes for Visible Surface Detections (Computer Graphics, CSC214): what the TU syllabus asks and how it has actually been tested, with 5 solved past questions from this unit.
What this unit covers
- Image Space and Object Space Techniques
- Back Face Detection, Depth Buffer (Z-buffer), A-Buffer and Scan-Line Algorithms
- Depth Sorting Method (Painter's Algorithm)
- BSP tree Method, Octree and Ray Tracing
Back Face Detection, Depth Buffer
Compare the Scanline Method for Visible Surface Detection with the Depth Buffer Method. [5]
The Depth Buffer method uses two buffers: - Depth Buffer (Z-buffer): Stores depth (z) values for each pixel position (x, y) as surfaces are processed. - Frame Buffer: Stores the color/intensity value at each pixel position (x, y). 1. Initialize each pixel o...
Full solved answer →Differentiate between object space and image space methods of hidden surface removal. Describe the Z-buffer hidden surface removal algorithm.[10]
Feature Object Space Method Image Space Method --------- Coordinate System Implemented in physical (world) coordinate system Implemented in screen coordinate system Basis of Decision Compares objects and parts of objects to each other within the scene to de...
Full solved answer →What is the advantage of real time rendering over offline rendering? Discuss the limitation of Z-Buffer algorithm. [5]
--- Real-time rendering and offline rendering are two major approaches used in computer graphics. Feature Real-Time Rendering Offline Rendering --------- Speed Renders frames instantly (30-60+ FPS) Can take minutes/hours per frame Use Case Games, simulation...
Full solved answer →BSP tree Method, Octree and Ray Tracing
What is the role of ray tracing in visible surface detection? Explain How scan line algorithm is used for back face detection. [5]
--- Ray tracing is an image-space method for visible surface detection. The basic idea is to trace the path of light rays from the viewer's eye (or camera) through each pixel on the projection plane into the scene. 1. For each pixel on the screen, a ray is ...
Full solved answer →List any two disadvantages of BSP tree method in visible surface detection. Make a comparison between Painter’s algorithm and A-Buffer algorithm.[10]
--- Based on the properties of BSP trees in visible surface detection: 1. High Preprocessing Cost / Complex Tree Construction: The BSP tree must be built before rendering begins. Constructing the tree requires selecting partitioning planes and recursively s...
Full solved answer →Make Unit 7 stick
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