This is the layout schematic of Castle Vianden, not Lucard's castle. However, one might surmise that Lucard's castle is the same in some ways--for example, as their outsides are identical, it's pretty safe to assume that both castles have four levels and a similar overall shape. One obvious difference between Lucard's castle and Castle Vianden is that Lucard's castle has corridors, whereas Castle Vianden is merely a series of interconnected rooms.
Lucard's Great Hall corresponds to the Knight's Hall in Castle Vianden and was filmed there in the pilot episode. Castle Vianden's dining room was also used in the pilot; even the furniture is the same. It's interesting to note that Castle Vianden has a chapel; if Lucard's castle does as well, one must assume that it is not open!

See also:
Castle Layout /
Lucard's Home Page /
lpetix@dpcc.com