BRL-CAD is a powerful solid modeling system designed to interactively create and analyze 3D geometric target descriptions. BRL-CAD includes an interactive geometry editor (MGED) using Tcl/Tk to provide the graphical user interface with pull down menuing and on-line help, a ray tracing library, two ray-tracing based lighting models, a generic frame buffer library, a network-distributed image processing and signal-processing capability, and a large collection of related tools and utilities. BRL-CAD supports a great variety of geometric representations, including an extensive set of traditional Combinatorial Solid Geometry (CSG) primitive solids such as blocks, cones and torii. Solids can be made from closed collections of Uniform B-Spline Surfaces as well as Non-Uniform Rational B-Spline (NURBS) Surfaces; purely faceted geometry; and n-Manifold Geometry (NMG). Geometric objects may be combined using Boolean set-theory operations such as union, intersection, and subtraction. BRL-CAD also supports a rich objectoriented set of extensible interfaces through which geometry and attribute data are passed to other applications. BRL-CAD runs on SGI, SUN, and PCs under BSDI/LINUX/Net BSD, and Other UNIX based Operating Systems.

Input
BRL-CAD input includes coordinate and vector description data for all components included in the 3D geometric target description. Inputs can be manually entered through MGED or procedurally through shell scripts and programs. Additional inputs include material lighting properties such as reflectivity, transparency, and color.

Output
BRL-CAD primary output is a 3D geometric target file in machine dependent binary format. Additional output includes a neutral ASCII file format, wireframe plots, rendered images, LOS data files, and text summary files (e.g., component code list, solid primitives with coordinate parameters, and object overlap interferences). Additional tools are also available for managing and enhancing image files, generating animation, and converting to/from BRL-CAD format.