Ah yes this one was very funny !
A French guy made a cool tuto presentation of it! (2003) Expression 3 - Creature House
alas some images are not more available! :(
http://web.archive.org/web/20031028183807/http://www.3dvf.com/modules/publish/Logiciels_817_1.html

Ps have you a free version for windows 10 ? Where can we download it ? i found for the moment only a mac version...