Electronic Visualization Laboratory, University of Illinois at Chicago, Chicago, Illinois, United States of America.|Laboratoire Bordelais de Recherche en Informatique, University of Bordeaux, Bordeaux, France.|Biomedical Image Informatics Department, VRVis Research Center, Vienna, Austria.|Department of Computer Science, University of Utah, Salt Lake City, Utah, United States of America.|Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America.