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Double-Sphere Computer Graphics Representation for Atoms

IP.com Disclosure Number: IPCOM000100318D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 88K

Publishing Venue

IBM

Related People

Pickover, CA: AUTHOR

Abstract

Disclosed is a computer graphics method for representing electron density of atoms using spheres. The traditional atomic representation uses a single opaque sphere. Here, an additional outer sphere, which surrounds an inner opaque sphere, is used, as shown in the figure. The outer sphere is semi-transparent and can represent a van der Waals radius, an s-orbital, outer electron shell, etc.

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Double-Sphere Computer Graphics Representation for Atoms

       Disclosed is a computer graphics method for representing
electron density of atoms using spheres.  The traditional atomic
representation uses a single opaque sphere.  Here, an additional
outer sphere, which surrounds an inner opaque sphere, is used, as
shown in the figure.  The outer sphere is semi-transparent and can
represent a van der Waals radius, an s-orbital, outer electron shell,
etc.

      This method is of particular interest to those incorporating
sphere graphics primitives and transparency attributes into 3D
graphics libraries.  The method is very easy to use with spheres.  A
useful transparency value for the outer sphere is 0.3, where 1 is
opaque and 0 is completely transparent.

      As an example, in the figure a portion of a super-conductor
lattice was created using a graphic primitive called a "polysphere"
(i.e., n spherical surfaces at given centers with specified radii).
The polysphere primitive is one of several 3-D extensions to the
PHIGS + and X-windows standard.  Lighting of the shapes was applied
on a primitive by primitive basis; no interactions between objects,
such as shadows or reflections, were defined.  The reflectance
calculation is conceptually applied at points on the spheres being
lit and shaded and produces color at these points.  Input to the
reflectance calculation includes the position on the primitive at
which the reflectance equation is being applied...