Real image (such as the images on the right), real rays of light are always represented by full, solid lines; perceived or extrapolated rays of light are represented by dashed lines. A real image occurs where rays converge, whereas a virtual image occurs where rays only "appear" to converge. Real images can be produced by concave mirrors and converging lenses, only if the object is placed further away from the mirror/lens than the focal point and this real image is inverted. As the object approaches the focal point the image approaches infinity, and when the object passes the focal point the image
WHAT IF software WHAT IF software WHAT IF is a computer program used in a wide variety of computational ("in silico") macromolecular structure research fields. The software provides a flexible environment to display, manipulate, and analyze small and large molecules, proteins, nucleic acids, and their interactions. The first version of the WHAT IF software was developed by Gert Vriend in 1987 at the University of Groningen, Groningen, Netherlands. Most of its development occurred during 1989-2000 at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany. Other contributors include Chris Sander, and Wolfgang Kabsch. , the software is maintained by the "Vriend group" at