CGDC '97 Roundtable Reports

Abstract:

To successfully create believable polygonal databases for use in a real-time 3D game, both the database developer and the application designer must consider the many aspects of such a design. Issues to be discussed will include database optimization, subdivision, level-of-detail, culling, frame-to-frame coherence, and texture mapping.

A database builder needs to maintain a balance between creative freedom and system requirements. An important issue is how to effectively tailor a visual database for maximum operational efficiency within a given image generation pipeline.
A application designer has the responsibility of how best to engineer a system that allows world builders to create a visually pleasing database within the minimum restrictions. A good system must maintain a high frame rate while reducing design limitations and artifacts.

SUBJECTS

3D Organization:

Use the texturing concept of MIP-mapping and apply it to models. Each model can have "MIP levels" or versions that have half as many polys and then half again and so on. The need to automate the process was brought up. Currently, it is very labor intensive. Any automated tools out there for creating LOD's of 3D models.
Data can be compressed using 3D world specific algorithms, then expanded only when near the view-volume. Any specifics?
The concept of "coherence" was discussed (sometimes using different names). The database designers need to decide what the structure of the database is and limiting the development tools or exporters to remain within the coherence. Share some formats anyone?

Database Tools:

The need to devote programming resources to build and maintain development tools for the artists or database builders.
Artists/designers are clever enough to extend tools or format to do more than originally designed. Provide and support this effort. Any good examples?

Optimizing for Object Interaction

Collision Detection:

Produce separate collision version of database which conforms or is automatically created from actual visual database.
In the MultiGen format, one designer is using the lowest LOD level for collision.

Height Above Terrain (HAT):

Drop vectors from HAT points and do a point inside poly test. If true, use poly plane to determine height.

File Formats:

VRML 2.0 is becoming a popular choice to investigate. The richness of format along with the ability to user-define or extend it, is making it a popular open 3D format. There were no examples of commercially available games currently using it. See http://vrml.sgi.com/moving-worlds/index.html for more information.
The majority of formats being used were proprietary. Any other formats proving successful?

Tools-Buy or Build:

The consensus was that buying them was better, but there are still a few people continuing to build their own. However, even most of the people buying tools were doing some custom work to either convert or enhance these tools. Plugins for modeling tools was a hot topic.
Some popular model or world building tools: 3D Studio, SoftImage, GameGen. Any others?

Targeting Multi-Platforms:

There were only a few people actively working on this problem. One approach is to use a greater range of LOD (level of detail) versions to produce the same database for different target platforms, especially if these target machines vary greatly in storage and through-put requirements.

3D Characters
Coupling with Rational Databases
NPS Net, DIS
3D Hardware
Geographic Info Systems

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