PRESENTATION OF THE SIGMA-SOFTWARE - SOFTWARE OF IMAGERY AND GRAPHICSFOR MOLECULAR ARCHITECTURE

Sigma (Software of Imagery and Graphics for Molecular Architecture) is a software package designed for visualization and exploration of thre e-dimensional (3D) molecular electron microscopy data. It comprises a text and two graphic modes. In the text mode, a language allows the wr iting of scripts for repetitive tasks. The two graphic modes are based on the multiwindow environment with a mouse as pointer. The first gra phic mode is dedicated to vectorial objects and the second to pixel/ v oxel objects, The data imported by SIGMA have various origins such as 3D reconstruction volumes, Protein Data Bank data, or geometrical obje cts like spheres, cubes, or cylinders. These 3D objects are interactiv ely rotated, translated, and rendered with SIGMA. This software, writt en in C language, runs on Silicon Graphics workstations using the X-Wi ndow plus Motif environment. The specific 3D routines are based on the Silicon Graphics GL library. (C) 1996 Academic Press, Inc.