SADXLVL is a VB.NET program for windows that allows the user to open and modify an Action Stage layout for Sonic Adventure DX: PC.
Note: you may need to have the
DirectX Runtime installed for this to work.
Features:
- can open and edit levels directly from the EXE
- highlights the selected level model.
- allows you to edit and reposition the collision data.
- can open and edit SET files using SETedit's code.
- is capable of retrieving various information from a running process, such as sonic's location.

Download here:
http://x-hax.cultnet.net/MainMemory/SADXLVLsetup.exeFor tutorials here:
http://www.youtube.com/watch?v=3q4VEAL07Dc by Main Memory
http://www.youtube.com/watch?v=1hLiD39hP9c by 11Supersonic11