The Materials and Geometry Format

Version 1.0, May 1995

Greg Ward, Lawrence Berkeley Laboratory, GJWard@Lbl.Gov


What makes MGF special?

What does MGF look like?

MGF's place in the world of standards

MGF was developed initially to support detailed geometric description of light fixtures for the IESNA luminaire data standard, publication LM-63. Existing standards for geometric description were either too cumbersome (e.g. Radiance) or did not include physical materials (e.g. IGES). It was noted early on that a standard able to fully describe luminaires would necessarily be capable of describing other objects as well; indeed whole environments could be defined this way. Since the descriptions would be physical, they could serve as input to both lighting simulation and rendering software. A standard language for describing the appearance of physical objects has been lacking for some time, and current efforts in this direction (i.e. STEP) seem several years away from fruition. (There are other languages for describing realistic scenes that deserve mention here, such as VRML and the Manchester Scene Description Language, but none give specific attention to physical material properties and are thus unsuitable for lighting simulation.)

In short, we saw this as an opportunity to offer the lighting and rendering community a simple and easy-to-support standard for describing environments in a physically valid way. Our hope is that this will promote sharing color, material and object libraries as well as complete scene descriptions. Sharing libraries is of obvious benefit to users and software developers alike. Sharing scenes should also permit comparisons between rendering systems and intervalidation of lighting calculations. As anyone who works in this field knows, modeling is the most difficult step in creating any simulation or rendering, and there is no excuse for this data being held prisoner by a proprietary data format.

MGF Basics

Entities and Contexts

Hierarchical Contexts and Transformations

Detailed MGF Example

MGF Entity Reference

MGF Translators

MGF Parser Library

Application Notes

Relation to Standard Practices in Computer Graphics

Relation to IESNA LM-63 and Luminaire Catalogs