Building An Interactive, 3-D Virtual WorldRaymond H. Mazza, Computer Science, Colby College

rhmazza@colby.edu http://www.cs.colby.edu/~rhmazza/Advisor: Randolph M. Jones, Computer Science, Colby College

+

Terrain Mapping

1. Model landscape. 2. Design texture with color placement proportional to desired height. 3. Map cylindrically to model.

Future Work• Genetic algorithms for object

creation (in progress)• Octree Implementation• Light Reflections on flat surfaces• Shadows• Bump-Mapping• Complex Animation & Scene

Graphs• Stereovision and head tracking

Acknowledgements• Varian.Net provided the geometry for the leafless tree seen the overhead picture up top.• 3DCafe.com provided the geometry for the tombstone, bridge, fountain, picture frame,

gargoyle head, and the leafy tree.• TotallySeamless.com was the source of most of my textures.• Wiremonger.com provided the grate texture used in the gallery.

Resources[1] 3D Studio MAX Release 3. Online. Internet. [April 16, 2000]. Available WWW:

http://www2.discreet.com/products/d_products.html?prod=3dsmax[2] 3D Exploration. Online. Internet. [December 14, 2000]. Available WWW:

http://www.xdsoft.com/explorer/[3] OpenAL.org. Online. Internet. [April 16, 2000]. Available WWW:

http://www.openal.org[4] OpenGL.org. Online. Internet. [April 16, 2000]. Available WWW:

http://www.opengl.org[5] Wright Jr., Richard. OpenGL SuperBible, Second Edition. Waite Press, 1999.

The ChallengeCreate a virtual world that integrates very realistic representations of form, sound, structure, physics, and interaction.Accomplishing this integration in an interactive system introduces a number of technical challenges. In particular, polygon counts and expensive operations must be limited, and the limits must not prevent the world from being interesting or aesthetic.Addressing these issues demands specific solutions for dealing with terrain, scene layout, fog, blending, special texturing techniques, collision detection and reaction (“clipping”).

BackgroundThe current state of computing enables very high resolution representation of graphics, sound and music, 3-dimensional world structure, physical simulation, and real-time interactivity.Computer systems that integrate these capabilities inevitably include tradeoffs in realism, especially when real-time interaction is a requirement. But modern computers make full high-fidelity integration increasingly feasible.

AccomplishmentsThe virtual world is both technically realistic and aesthetically pleasing. It will serve as a basis for further work and more in-depth research. Features include:

•Adaptable particle engine for snow, liquid, and other particle simulation.•Efficient collision detection and collision reaction.•Element of time with day and night, and synchronized lighting and fog effects.•Terrain Mapping for realistic, 3D background.•Effective use of blending, dynamic textures and multi-texturing for sky and water visual effects.•External texture work for ad-hoc polygon textures.•Dynamic 3D engine can be manipulated by users at run time, to understand its mechanisms.

Above: Collision boundaries for the walls and ground in a bumpy mountain path.

Bottom Left: Ray-Casting from the cylindrical viewer boundary towards many of the wall and ground boundaries. The 6 points drawn are where the rays intersect with planes these polygons lie on (but do not intersect the actual polygon).

Bottom Right: Some cylindrical boundaries in a castle courtyard.

Collision Detection and Reaction

Particle Engine

Bottom Left: Thousands of blue particles are spewed from a fountain to simulate water. They have lifetime-dependent alpha values and have a negative force due to gravity acting on them.

Bottom Right: The particle engine creates a snow effect. It generates 10,000 particles with constant negative Y-velocity. Particles regenerate upon hitting the plane Y=0, where the ground is located.

PROGRESSION

of Time

Day Dusk Night

3. Same scene, no lighting

4. Grove scene again, with lighting2. Grove scene in wire frame

1. Image appears on tomb when clicked

8. Human & Computer DNA on Pillars6. Beach with moving water on shore

7. Art gallery (Escher on left)5. Misty underground lake