How is Wii U ripping happening?

[Ray Koopa]

Yeah, I wondered that too a month ago, and researched the internet a bit to get the Koopalings out of MK8.

Basically, to get access to the files, this is how I understood it (no warranty about correctness):

• Option A: The Wii U optical drive seems to be a generic SATA drive, requiring a modded SATA cable to connect it inside your PC, and a driver to talk to its custom firmware which Nintendo made. Then use some raw data ripping program to read the data. Heavily simplified of course - I remember people talking about some "key" required to be able to talk to the drive at all and get its responses, I didn't read more about that yet.
  
• Option B: In combination with an exploit, you re-route the Wii U disk access over your local network, and a possibility would be to make it write the read disk contents into a network stream, which you fetch on your PC, thus, slowly recreating the game's contents on your PC hard drive. The original Cafiine server is capable of dumping specific requested files (more details about how to are found with Google); my version of it dumps all the files ever queried.
  
• Option C: You let someone else go through this hardware / software modding hazzle, let him upload the ripped disk image or DLC contents, and download it as a torrent. You're dependent upon rippers releasing the raw image as a torrent then, and can't just say "Today, I rip Pikmin", of course.
  
• Option D : For DLC content, there is a downloader tool called UWizard to download the update files from Nintendo's servers, handling all the specific network communication stuffs required to successfully do that. You still don't get paid content this way, it seems. You need the other options to access them after you bought them.
  

If you got the raw image or DLC data, you still have to decrypt it, which requires a common key and a title key, acting like two passwords needed to decrypt everything.

• The common key is stored in the Wii U and thus always the same for any game. It has been ripped and floats around in the web.
  
• The title key is stored on the disk image at a constant offset (I don't really believe it's that simple, but that's what I heard), and thus differs for each game title. Again, most keys have found their way into the web.
  

With that, you can decrypt the disk image with DiscU and get its single files, which often turn out to be compressed SZS files for bigger stuff (like a ZIP file containing a compressed file), or directly uncompressed files like BFRES (a container for model data (vertex data, bones, materials) / textures / animations, of which not all sections have been parsed yet, most prominently the animations and shader programs AFAIK).

There are many tools to convert from SZS/BFRES to *insert your preferred model format here*. What I do is convert to DAE for rigged characters (as it supports bones) and to OBJ/MTL for static models (like Mario Kart 8 base track models, as it doesn't support bones which static models don't have anyway and is more widely supported).
My workflow is basically like this:

1. Unpack SZS files with EveryFileExplorer (they are Yaz0 compressed) to get the BFRES file out of it.
   
2. Unpack the single files of the BFRES model with LordNed's BFRESExtractor, and keep only the GTX files in the 1_FTEX folder, representing the textures.
   
3. You can convert these with TexConv2 into DDS textures. Put them back in the same folder as the BFRES file. You can get rid of the empty 1_FTEX folder and the others now (keep the BFRES itself).
   
4. Use RandomTalkingBush's / ItsEasyActually's MAXScript to import the BFRES file into 3DS Max (yes, you need to get that large application from somewhere too), and run it there by selecting the BFRES file.
   
5. Fix the model. I normally remove the duplicate layers (which represent a messy texture layer at the moment), rotate it up-right, maybe remove doubled vertices to fix smoothing and get rid of loose vertices which are unneeded. Some character models may need pupil bone repositioning or their eyes float around outside.
   
6. Export to DAE or whatever you like (maybe use the OpenCollada DAE export plugin for 3dsMax as the preinstalled Autodesk DAE exporter is a wreck).