This is a very incomplete list of researchers
Tim Dwyer (3D UML using force directed layout.)
Jens von Pilgrim (GEF3D - an Eclipse GEF extension bringing 3D to diagram editing)
Stephan Diehl (Software Visualisation)
Juergen Rilling (Software Visualisation)
Peter Eades (Software Visualisation)
Colin Ware (Information Visualisation)
Christopher Collins (Information Visualisation)