Papyrus is a graphical editing tool for UML2 as defined by OMG. Papyrus targets to implement 100% of the OMG specification. Papyrus provides a very advanced support for UML profiles. Every part of Papyrus may be customized: model explorer, diagram editors, property editors, etc.
Papyrus also provides a complete support to SysML in order to enable model-based system engineering. It includes an implementation of the SysML static profile and the specific graphical editors required for SysML.