INTRO: This will be step by step walktrough of how to make a engine mod, it is for absolute beginners and shows how I do things, which might be different from how others do it, but should be something that helps you started.TOOLS:
Recommended: Notepad++ from https://notepad-plus-plus.org/
Optional: Torsion's tutorial to get most out of Notepad++ https://www.beamng.com/threads/how-to-enable-proper-highlighting-in-notepad.39158/#post-588554
Recommended: 7-zip http://www.7-zip.org/-------Let's begin-------
Official vehicles are in zip files at (Program Files (x86)\Steam\steamapps\common\BeamNG.drive\content\vehicles), however hold your horses there!
It is not good idea to edit files in that location as it messes up with the game, instead it is better to make changes in a mod folder.So anything you drop into your (Documents\BeamNG.drive\mods) folder overrides what is in game folders.
Step 1:
Let's start modding by creating a temporary location where we extract (Barstow.zip)I made these folders (moddingtuts\stage 1\more power to Barstow\original)
Step 2:
Extract official Barstow vehicle, you can find Barstow in following location (Program Files (x86)\Steam\steamapps\common\BeamNG.drive\content\vehicles\barstow.zip), notice how there are vehicles and barstow folders inside the zip file (archive), that is very important to remember later.Drag vehicles folder from inside of the Barstow.zip to folder named original and you should have something like this:
Step 3:
Create new folders inside more power to barstow folder, first create vehicles folder, then inside of vehicles folder create folder named barstow.NOTE: We don't use capital letters now, it is good practice to avoid capital letters if original files and folders don't have capital letters so you maintain same logic and later it becomes more important when editing files.
Step 4:
Now we must copy barstow_engine.jbeam to barstow folder we created at previous step as illustrated by next image, make sure you copy, default action is to move, so hold ctrl down when dragging or select copy and then choose folder and paste!:Step 5:
Next is fun part, we open barstow_engine.jbeam and start modding, IMPORTANT make sure you open correct file, not one that is in (original) folder, but one that is where you copied engine file in previous step as shown by this image:
You will have more fun if you installed Notepad++, if not yet, now is good time for that, links at top of post.Step 6:
INTRO:
Each jbeam file will have brackets and commas, all very important, curly bracket defines begin and end of section.
Line 1 has opening of jbeam file curly bracket, line 2 has name of part section "barstow_engine_v8_291": and also at end of line 2 there is curly bracket that opens up part section. I have placed blinking cursor next to that bracket on line 2 so you can see it glows red, this is handy feature of Notepad++
Line 161 has closing curly bracket which is end of barstow_engine_v8_291 part, Notepad++ makes it glow red so it is easy to find:
More information about jbeam file structure: JBeam_Reference
Step 7:
So now we know that what makes engine is between lines 2 and 161, next we select all of those lines, including line 2 and line 161 with everything between them, copy that and paste to new file, so select like in image and copy selection to clipboard.
Then hit new button from toolbar and paste selection from clipboard and you should end up something like this:
Step 8:
Next save file to (more power to Barstow\vehicles\barstow) with new name, I like to use my name at end of jbeam file name to make less chance of someone's mod conflicting with mine.
IMPORTANT: Select Save as type to All types (*.*) or else your file will not be .jbeam, it will be .txt and that is not working in game.Step 9:
We now have a part (engine) in our new file, but we don't have curly bracket on line 1 that opens the file, so we need to add that and his friend that closes the file at end of the file. So make cursor blink at beginning of line 1, hit enter and make cursor blink at line 1 again, put opening curly bracket there like in image:
At this point many make a mistake, at end of the file at line 161 there is curly bracket and it closes something, if you put blinking cursor next to that curly bracket on line 161 it turns red as in image:
It is good practice to scroll up and see which curly bracket is pair of that one, in this case it is actually opening bracket for engine part and not the file, so it means we need to add one more curly bracket to end of file so you should have something like in image.
Then change name of engine at Line 2 and at Line 5, different between these two is that name on Line 2 is used by game internally and Line 5 is what you see in game:
Step 10:
Now that we are all set, we can start to make the changes, so I decided to change torque curve to what I happened to have from Ford 428 Cobra Jet, I made quick chart of numbers with 500rpm resolution:
You can also see typical problem with dyno data, it does not go to low rpm and you have to estimate what 500rpm to 2500rpm range would be, research, read a lot, watch videos, try to find more data, that takes timeSo, what I usually do is this:
So what I'm doing here is aiming for smooth curve, that does not kink quickly up or down, for example I could type in values like this:
Of course testing, driving, researching etc. is required to get it properly right, also engine's dynamic friction parameters eats up some power, so does transmission, differential etc. So when you have dyno numbers that are torque from the wheels, you need to increase torque in engine file to get same torque to wheels as IRL, use torque curve app in game to see how it looks and adjust accordingly to get correct amount of power.If you don't know how to make charts in Excel, you can look tutorial from YT about it, there should be plenty. I made RPM lines with shapes, just drew some lines there to make it easier to read.
Step 11:
After you have spent hours and maybe days of researching to make realistic engine, have got torque curve nice and smooth, it's time to put numbers in (of course you can slap any random numbers you like, but that does not make quality mod).So under mainEngine we have section called torque and it opens with '[' and also closes with ']' inside the torque section we have rpm bins, for example [500, 380], defines 500 rpm at full throttle engine produces 380Nm of torque.
Note that I added new RPM bins there and changed rpm numbers from original, also below torque section I changed maxRPM to be 6000, can't remember now exact maximum rpm for engine, it depended from year I think and later ones had something bit over 6000rpm limiter I think, earlier ones did self destroy without limiter after some high rpm abuse, but for purpose of tutorial I believe 6000rpm will be fine, you can change that to whatever you wish.Save changes!
Step 12: Getting new motor into game
First we can get rid of barstow_engine.jbeam that we copied to our work folder in (more power to Barstow\vehicles\barstow) so delete that:
Open more power to Barstow folder and compress vehicles folder with right mouse button click like in image:
You should have something like this, you can really name zip anything you like, good idea to add your name and maybe even version number so it will not be conflicting:
Contents of zip should be like this:
Step 13: Testing mod in game
Drag and drop mod normally to Documents\BeamNG.Drive\Mods and test in game your engine should appear in list like here you can see mine named as 428 CJ V8 EngineNOTE: make sure to use 4bbl carburetor intake as with 2bbl your brand spanking new torque curve will be ignored!
That is just the beginning, we did not even touch slots yet and that is one important aspect that you need to learn, check Wiki it has information, but sometimes bit hard to digest form. Also when working with bigger project there is ways to get changes to game faster, but for start this should help a bit, you should now be able to make new parts for the car, like engines and transmissions.
Making 3d models and textures is tutorial that someone else will (hopefully) make. This took me over 2 hours to botch up.
More information: CombustionEngine
