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What Sabrina Does

Sabrina is an interactive, three-dimensional geometry modeling program, used primarily in support of MCNP, a Monte Carlo code for neutron, photon, electron, and other particle transport simulations. Sabrina produces 3-D images of MCNP geometry, permitting visual verification of the model. The user may also construct either body geometry or surface geometry models from scratch. Models described in terms of combinatorial body geometry can be converted to surface geometry descriptions that can be read by MCNP. Use of Sabrina reduces the effort required to construct, debug, and verify complicated 3-dimensional models. In addition to simply seeing if a model "looks right,", Sabrina can check for undefined and overdefined space throughout a model.

Both a ray tracing algorithm and an edge finding method are available for visualization. Cutter bodies may be used to show the interior of models. An X-ray simulation mode is available. The spatial tracks of particles, as calculated by MCNP, may be displayed. Sabrina can read and write the geometry block of input files for the ACCEPT code of the Integrated TIGER Series (ITS) codes.

Sabrina is available in versions for Windows on personal computers and for UNIX. The Windows version works under Windows95, and WindowsNT. The UNIX version runs on computers from simple workstations to UNICOS on CRAY computers. Ports to other hardware and operating systems can be made. In the UNIX version, the X Window system is used for displaying graphics on a workstation or terminal screen. Sabrina supports color models from monochrome to 24 or more plane true color. Sabrina generates PostScript files for hardcopy. UNIX Sabrina also writes GIF files. Windows Sabrina writes Device Independent Bitmaps (.bmp or .dib). Either version can send the respective image format (PostScript in UNIX, bitmap in Windows) to a printer.

A help facility supplies a few words to a few paragraphs on each command. The Unix version uses hypertext (html) help that is displayed by Netscape Navigator.

Sabrina can write a dump of the geometry model for later use by Sabrina. The geometry may also be written out in MCNP input format.

The volume fraction feature, invoked with the VOLFR command, calculates material fractions on a rectangular grid. The grid, which need not be uniformly spaced, is defined with the Mesh command. The feature is available for surface geometry.