Advanced Graphics and HCI

Lecturers: Dr N.A. Dodgson and Dr A.F. Blackwell
(nad@cl.cam.ac.uk and afb21@cl.cam.ac.uk)

No. of lectures: 16

Prerequisite course: Computer Graphics and Image Processing

Aims

This course will develop an understanding of three-dimensional modelling and rendering techniques to a deeper level than the Part IB Computer Graphics and Image Processing course. It will facilitate the design and analysis of user interfaces.

Lectures

Part A. 3D modelling [8 lectures]

• Revision. Revision of the ray tracing, polygon scan conversion, and line drawing methods of making images from 3D models; the pros and cons of each approach. [0.3 lecture]

• The polygon. Drawing polygons. Hardware speed-ups. Polygon mesh management: data structures. [0.5 lecture]

• Other geometric primitives. Plane, sphere, cylinder, cone, box, disc, torus. Ray intersection calculations for ray tracing. Calculating the normal. Converting the primitives into polygons for use in polygon scan conversion. [1.2 lecture]

• Splines. Revision of Bezier curves and surfaces. B-splines, from uniform, non-rational B-splines through to non-uniform, rational B-splines (NURBS). [2 lectures]

• Subdivision surfaces. [1 lecture]

• Other ways to create more complex geometry. Generative models: extrusion, revolution, sweeping, generalised cylinders. Constructive solid geometry (CSG): set theory applied to solid objects. Implicit surfaces and voxels: 3D pixels and the marching cubes algorithm. [2 lectures]

• Lighting. Revision of the basic diffuse + specular + ambient approximation. Radiosity: solving the inter-object diffuse reflection equations to produce more realistic images. [1 lecture]

Part B. Human-computer interaction [8 lectures]

• Introduction: cycle of dialogue. The human virtual machine: Hick's Law, model human processor, Fitts' Law, power law of practice.

• System evaluation: usability analysis, GOMS, keystroke level modelling. Conceptual design and mental models.

• User interface design: cognitive walkthrough, design and evaluation of user trials.

• Novel user interfaces.

Objectives

On completing the course, students should be able to

• produce equations for each geometric primitive, derive a ray/primitive intersection algorithm for each, describe how each can be approximated by polygons

• define NURBS basis functions, understand the use of NURBS curves and surfaces in 2D and 3D modelling, explain why NURBS are used in preference to other curve and surface specification mechanisms

• describe and explain how to use generative models, constructive solid geometry, implicit surfaces, voxel rendering and subdivision surfaces; describe how each representation can be converted to polygons

• explain the radiosity algorithm

• describe the human virtual machine and derive quantitative models from it

• use psychological models to analyse an interactive system

• apply a range of techniques to predict the behaviour of user interfaces

• design and undertake an experiment to evaluate a novel user interface

Recommended books

Foley, J.D., van Dam, A., Feiner, S.K. & Hughes, J.F. (1990). Computer Graphics: Principles and Practice. Addison-Wesley (2nd ed.). [3DM]
Rogers, D.F. & Adams, J.A. (1990). Mathematical Elements for Computer Graphics. McGraw-Hill (2nd ed.). [3DM]
Newman, W.M. & Lamming, M.G. (1995). Interactive System Design. Addison-Wesley. [HCI]
Borenstein, N.S. (1991). Programming as if People Mattered. Princeton. [HCI]