G3toG4 (rztog4+call list interpreter) provides a mechanism to instantiate G4 geometries using information obtained from G3 data structures.

• many bugs in G4 geometry code were discovered and fixed using this tools
• no known mechanism to retrieve components of mixtures from G3 data banks, so mixtures cannot built up from their components on the G4 side using the rztog4 ? call list interpreter (mixtures problem)

EucIntfce abstract Geant interface is a useful G3/G4 validation tool requiring some C++ coding, but does not suffer from the mixtures problem

Areas needing work:

• handling of divided volumes (G3toG4)
• sensitive detectors and hits (G3toG4)
• shapes in G3 missing in G4 (eg, HYPE)
• booleans