*vlib* (short for "volume library") is a programmatical interface between a high-level volume modeling program and a lower-level volume-based rendering and voxelization system. It provides a coherent and consistent approach to modeling using several dozen commands which support the majority of significant trends in volume graphics. In particular,

- multi-object modeling;
- constructive volume geometry;
- shadows, reflection and refraction with recursion control;
- solid textures, hyper-textures and distance fields;
- direct volume rendering with controllable color accumulation and sampling intervals;
- direct, multiple iso-surface rendering accommodating semi-transparent surfaces;
- the maximum intensity projection rendering algorithm;
- linear ramp and lookup table transfer functions;
- spatial deformation permitting arbitrary user-defined effects such as tapering, bending, twisting, pulsating, cracking and exploding;
- nearest neighbour, trilinear and user-definable BC-spline tricubic filters for interpolation and gradient estimation;
- object clipping;
- rotational sweeps;
- adaptive super sampling for greater image quality;
- multi-chromatic directional and attenuating point light sources;
- user-definable normal perturbation for bump-mapping and similar effects.

The consistency offered by the system in modeling complex solid and amorphous matter effectively unifies a variety of rendering schemes that would otherwise remain largely independent.

In the context of the interface, a volume object employs ten cospatial bounded scalar fields to represent its physical properties (e.g., color and opacity). These fields may be specified independently using a number of sound mathematical principles in order to achieve a high degree of flexibility using a collection of intuitive commands.

A complete implementation of the *vlib* API has been produced at the Department of Computer Science at the University of Wales in Swansea. The complete source code is available on this site for use under the terms of the GNU General Public License. Additionally, an accompanying auxialiary library, *vlaux*, is also available which contains a number of additional functions built on top of the existing functionality of the API.

- A. S. Winter and M. Chen,
**vlib: A Volume Graphics API**,*Volume Graphics 2001*, Mueller and Kaufman (eds.), pp133-147, Springer, New York, 2001. ISBN 3-211-83737-X.

- A. S. Winter and M. Chen,
**Image-Swept Volumes**,*Computer Graphics Forum*, volume 21, number 3, 2002.

- M. Chen, A. S. Winter, D. Rodgman and S. M. F.Treavett,
**Enriching Volume Modelling with Scalar Fields**, To appear in*Data Visualization: The State of The Art*, F. Post, G.-P. Bonneau and G. Nielson (eds), Kluwer Academic Press, 2002.

Click here to request further information.