NOTE: Other than for links and resources this is a VERY brief text-only run-down, DOWNLOAD the document for a 9,000+ word document with much more information and images (may seem a daunting number but much of that can be skipped and, hopefully, very readable).
* With just this GameBanana page = intermediate, might have to figure out things yourself but could be editing stages in a dozen-or-two minutes.
* With the updated download document = beginner but with larger time investment, everything is very explicitly explained down to installing required resources with images galore. Also has some higher-level stuff, so broader range but over more time, perhaps expect an hour-or-two before you really get going proper.
1. EXTENDED DOWNLOAD VERSION:From this page:
(Download the top file)
2. VITAL RESOURCES:Object Tables >
(list of object IDs required to edit set files manually, per level, some minor errors so be sure to test new objects)
Level Data Locations >
(What file is for what level)
Hexadecimal to Decimal conversion (and vice versa) >
(SET Adventure values are decimal but sometimes in-game are hex such as rotation, use to convert)
3. REQUIRED DOWNLOADS:Cheat Engine 6.4 >
MAKE SURE TO ONLY DOWNLOAD VERSION 6.4 (When the install asks for agreeing to terms of services DON'T ACCEPT as it's actually just asking to install McAfee)
Cheat Engine SA2 tables >
COPY CONTENTS INTO YOUR "CHEAT ENGINE 6.4" INSTALLATION FOLDER
SET Adventure >
(You may already have this if you've downloaded the SATools set)
4. OTHER USEFUL RESOURCES:BoostedBandCamps YouTube video tutorial >
(Which much of my knowledge came from.)
PaRappa64s texture editing tutorial >
Redstreak94s answer to edit stage music >
MainMemorys tool set for SA2 and other Sonic games >
5. LOCATION OF FILES TO EDIT:
5.1. Level Object files:[ Sonic Adventure 2 > resource > gd_PC > set00"aa"_"b" ]
Where "aa" = the stage number and "b" = what type of set file:
s = for mission 1 through 4
u = less important objects for mission 1 through 4 (and 5 if no dedicated hard u file)
hd_s/u = mission file (hard) level files, sometimes no dedicated u file
2p_s/u = 2 player files
5.2. Other level-related files:Fog:
[ Sonic Adventure 2 > resource > gd_PC > stg"aa"_fog ]
(Colour and strength, while not sure how to edit myself can copy fog files between levels by changing their name)
[ Sonic Adventure 2 > resource > gd_PC > ADX > "c".adx ]
Where "c" is usually an abbreviated name of the stages name in English, with a number after if multiple tracks per level. For example "c_escap3.adx" is City Escapes 3rd music track (I think used for the 2 player stage).
[Sonic Adventure 2 > resource > gd_PC > "daa".prs ]
[Sonic Adventure 2 > resource > gd_PC > PRS > "daa".pak ]
Where "d" = the type of texture files for the level, there are four:
"objtex_stgaa" = Stage objects, the unique stage objects you can edit in the set files
"landtxaa" = Level geometry (non set file objects usually)
"bgtexaa" = Sky-box
"stg_titleaa" = Name of the stage that appears on the loading screen
6. EDITING LEVELS PRIMARILY THROUGH CHEAT ENGINE:
6.1. From the Cheat Engine windows:1.) To activate Cheat Engine for SA2: with SA2 running past the main menu open Cheat Engine 6.4 and go to [File > open > bunch of numbers followed by: "sonic2app.exe"], press enter/click-"Yes" on 2 pop-up windows.
2.) To check coordinates click on "Info Display", will see position and other information overlay on your SA2 window.
3.) To edit with Cheat Engine 6.4 in your Tool tab click "Object Editing" then in the new window "Live Edit Mode" and then "Place Objects..." opening the Object Placement tab.
4.) In the Object Placement tab click on "Enable Object Placement" then "<-------Level Objects" (not "...Common..." as these can't be saved and are error prone.
5.) Choose object from list and click "Spawn Object" to object where cursor is...
6.2. From the SA2 window:1.) Toggle between cursor and object mode by pressing [v] "down" on the D-pad, triggers move cursor up/down (Y plane) and control stick for X and Z planes. Instructions are on screen. Switching to object mode snaps to closest object to cursor position.
2.) Whilst in object mode hold the D-pad...
[<] "left" to move the selected object.
[^] "up" to rotate object (if object CAN be rotated, not all can on all axis).
[>] "right" to edit var 1, 2 and 3 (sometimes scale, power, scripts for enemies, nothing or something else - object specific).
6.3. From Cheat Engine 6.4s window(s) again to save changes:1.) Click "Show Spawned Objects" then "Save to File...".
2.) DO NOT save over the original file, save as new name or new location and MAKE SURE to set the "Save as type:" as "Native SET format (*bin)".
6.4. From SET Adventure to create your file:1.) Open either newly saved file or level file you wish to amend (either the s or u, not too important), click on [File > Merge] and select the other file you didn't open then [File > Save As SA2] and save over the original level set file.
7. EDITING LEVELS PRIMARILY THROUGH SET ADVENTURE:
7.1. Getting position from Cheat Engine:(condensed repeat of prior info) With SA2 running past the main menu open Cheat Engine 6.4 and go to [File > open > "sonic2app.exe"], "Yes" on 2 pop-ups. Click on "Info Display", will see position on SA2 window.
7.2. From SET Adventure to edit:1.) Open file from SET Adventure, typically "s" is the main file and "u" more decorative assets. Anything with "hd" is for the hard mission, without usually for mission 1 - through - 4 but if no "hd_u" then "u" files also for hard mission.
2.) [Edit > Add Blank Object] to add new object, can change parameters by double clicking on it:
* Rotation may be self-explanatory but is object specific and can affect things other than rotation or have no effect depending, check object table notes. THESE ARE HEXADECIMAL values in-game but converted to decimal in SET, you will need to convert.
* X, Y and Z is position, use Cheat Engine to check coordinates.
* Variable 1,2 & 3 is often scale (and referred to as such in Cheat Engine) but can be various traits depending on object, again check object table.
Click "Apply" to add changes.
3.) To save is [File > Save as SA2] with the correct name.
4.) Can highlight multiple objects to delete or duplicate (from the "Edit" menu). NOTE after you duplicate objects save and re-load the file so you can edit duplicates without impacting source objects. Duplicated objects appear at the bottom.
X.) Tips - organise by [Edit > Organize], good practise to do before you edit so your additions are at the bottom and top of the list. To temporarily 'disable' an object change it's ID to '0' (always? a Single Ring) or add 10,000 to its Y position - anything obvious you can revert later.