def my_blenderbuilder(target, source, env): print "Hei!" return 0 def my_blenderbuilder_print(target, source, env): print "Hoi" return "I should build '%s' from '%s'" % (target[0], source[0]) myaction = Action(my_blenderbuilder, strfunction=my_blenderbuilder_print) mybuilder = Builder(action=myaction, suffix = '.zzz', src_builder = ['CFile', 'CXXFile'], src_suffix = '.xxx') env['BUILDERS']['BlenderXXX'] = mybuilder xxx = env.BlenderXXX(target='test.zzz', source='test.xxx') Default(xxx)