CMI CMI Digital Media & Interactive Visualization 1 — Questions and Answers
Question 1: In 3D medical animation, which rendering technique simulates light scattering through tissue for realistic skin appearance?
- Flat shading
- Subsurface scattering (SSS) (Correct answer)
- Cel shading
- Ambient occlusion only
Correct answer: Subsurface scattering (SSS)
Subsurface scattering simulates how light penetrates and diffuses within translucent materials like skin and soft tissue, producing photorealistic rendering.
Question 2: Which file format is the standard container for 3D medical models used in interactive anatomical applications?
- STL
- OBJ
- glTF/GLB (Correct answer)
- DXF
Correct answer: glTF/GLB
glTF (GL Transmission Format) is the modern standard for 3D content in web and interactive applications because it is compact, efficient, and supports materials and animations.
Question 3: In a medical animation pipeline, what does 'rigging' refer to?
- Compositing visual effects layers
- Creating a skeletal armature to enable character or anatomical structure movement (Correct answer)
- Setting up render farm nodes
- Mapping texture UV coordinates
Correct answer: Creating a skeletal armature to enable character or anatomical structure movement
Rigging creates a hierarchical skeleton of bones and controls that animators use to pose and move 3D anatomical models in a physically plausible way.
Question 4: Which web technology enables interactive 3D anatomical models to run directly in a browser without plugins?
- Adobe Flash
- WebGL/Three.js (Correct answer)
- Java Applet
- Silverlight
Correct answer: WebGL/Three.js
WebGL is a browser API for GPU-accelerated 3D graphics; libraries like Three.js build on it to deliver interactive 3D medical visualizations without plugins.
Question 5: In medical AR/VR applications, what is the significance of 'frame rate' for surgical training simulations?
- It affects file size only
- Rates below 60 fps can cause motion sickness and reduce training effectiveness (Correct answer)
- It determines polygon count
- Frame rate only matters for video export
Correct answer: Rates below 60 fps can cause motion sickness and reduce training effectiveness
VR simulations must maintain at least 60–90 fps to prevent cybersickness; lower frame rates cause visual-vestibular conflict that impairs training and causes nausea.
Question 6: Which approach is used in CT/MRI volume rendering to produce semi-transparent 3D medical images?
- Marching cubes algorithm only
- Transfer functions mapping voxel intensity to color and opacity (Correct answer)
- Boolean mesh subtraction
- Phong shading only
Correct answer: Transfer functions mapping voxel intensity to color and opacity
Volume rendering uses transfer functions that assign color and opacity values to voxel intensity ranges, revealing internal structures within a semi-transparent 3D volume.
CMI CMI Digital Media & Interactive Visualization 1
In 3D medical animation, which rendering technique simulates light scattering through tissue for realistic skin appearance?