How can i convert Penumbra models,monsters with same functions?

[Slanderous]

You can take some assets from modern mods such as Penumbra Necrologue, or White Night. You don't need to ask about the penumbra models as they are created by frictional games and just converted by these mods author's. Keep in mind if you want to use models created by mod creator's not frictional games, you should ask them. You can also take a look at the "Development resources" section of the development support, you can find many great and well-done things here.