export house from milkshape as either a .b3d,.x,.3ds file named for example "house.b3d".
in your blitz code do something like this:
graphics3d 800,600,0,2
camera=createcamera()
cameraspeed#=1.0
mesh=loadmesh("house.b3d")
if mesh=0 then runtimeerror("not a valid mesh file")
repeat
if keydown(200) then moveentity camera,0,0,cameraspeed# ;forwards cursor
if keydown(208) then moveentity camera,0,0,-cameraspeed ;backwards cursor
if keydown(203) then turnentity camera,0,1,0 ;left cursor
if keydown(205) then turnentity camera,0,-1,0 ;right cursor
if keydown(30) then moveentity camera,0,cameraspeed,0 ;A for up
if keydown(44) then moveentity camera,0,-cameraspeed,0;Z for down
updateworld ;although there should be nothing to update in this example
renderworld
flip
until keydown(1)
freentity mesh
freeentity camera
end