I am still working on a mod in Amnesia: The Dark Descent and I would like to continue this mod in SOMA. How do I make the entities/static objects from TDD work in the SOMA engine?
You can't open .map files with HPL3. For the time being, you'll have to reconstruct your maps in HPL3, though it's possible that .map files will be supported in the future. However, it might not be worth the time waiting for it rather than doing them over.