Creating levels for JSRF - an overview

Hey,
so for the past few months I have been working on the JSRF level compiler and also an add-on for Blender to export levels for JSRF, also the latest version of the JSRF Mod Tool processes and compiles the data into the game's level file format and boom! custom levels.

Once again huge thanks to Gurten, Daft, Demo, Fuse, Duck from the JSRF Reverse Engineering community & the Cxbx team who made this possible.

 
This post is an overview of the process, however I will not be covering the topic of the 3D modelling process since it would be too long to cover, it's a subject on it's own and there's already plenty of tutorials out there for Blender, the focus of this post is on how the JSRF levels work and the tools to create them.

Click here to download the JSRF Mod Tool and the Blender JSRF Stage exporter addon

In this zip file you will find a Blender scene file with a test level, the dev textures for the collision materials, the Blender JSRF Stage Exporter addon an the JSRF ModTool which compiles the level data exported from Blender, and lastly a Mission file which loads when you select "new game", the level will be empty, only corn is standing around, place this file in the "Media\Mission\" folder.

 

You can find the source code for the JSRF ModTool here

 

 

 

Composition of a JSRF level

A JSRF level is mainly composed of 3D models, of two kinds, one for the visuals that we see and uses textures (top left picture), and another, invisible in-game which is used for the physics simulation(top right pic) and how the player controller interacts with the environment's surfaces.

On the left the visual models, on the right the physics collision model, notice how the collision model has less detail, it's simplified, for instance the stairs become a flat ramp but in the game the yellow surfaces act as stairs and the character takes steps as if there were stairs.
The colors on the surfaces of the physics models help us recognize what type of physics material the faces of the model are assigned.

Lastly, the level also contains curves data for the rails we can grind in-game.

Setting up the Blender JSRF Stage Exporter

First let's install the JSRF Exporter addon for Blender, make sure you have downloaded the files, and have "JSRF_Stage_Exporter.py"

In Blender go to Edit >> Preferences >> Add-ons then click Install

Browse to and select "JSRF_Stage_exporter.py" and don't forget to tick the checkbox(highlighted in red here) to enable the add-on:

You can the find the JSRF Stage exporter menu at the bottom of the 'Scene' panel:

You will first need to setup the paths as follows:

Stage ID is the name of the stage it will be exported as in the Media\Stage\ directory

Stage Export Path is the folder where the Stage data will be exported

Media Directory should point to the JSRF Media folder

ModTool filepath should point to the JSRF_ModTool.exe

When you press Export Stage, the stage data from blender will be exported, then the JSRF ModTool will run and compile the stage (by default) as the Garage (stg00)

Creating the visual model & using it as a base for the collision

When we start to make a level, we're not going to work on the fancy visuals, instead we roughly model the shape of the level and objects, assigning the physics materials as the default material/texture for the visual models since that's what we're going to use as temporary collision models.

So you'll want to assign the materials that come with the demo scene.

Here's what a test stage looks like:

This is just a test map but that's all you need to know to get started making and testing levels for JSRF, if you're going to do the proper visuals.
You might want to use the old mod tool (download top right) to extract the game's models and textures to re-use them.


Here's what the scene in Blender should look like:

The main "Stage" collection contains "Visual" "Collision" and "GrindPaths", and the those three collections should contain other collections that contain the meshes, and curves for the GrindPaths collection, check how the demo scene is setup if you're not sure.

You must use this structure and naming (except for "Model_group_0" you can name those whatever you like) as that's how the JSRF Stage Exporter addon can process and export the level data.

As for collision models, you can have up to 1023 triangles per collision model group, that's just how the game engine works.


When you have blocked out your level's visual meshes(with the collision materials), as a shortcut you can copy paste the model groups from Visual collection into the Collision collection.
For a finished level the collision models should be modeled separately or you can use part of the visual models as a base, but the models should be simplified as much as possible, for instance, for a set of buildings as collision model, you wouldn't have multiple buildings/boxes for collision, but simply a big wall joining the ground with more or less the same scale as the buildings, in some cases it can be boxes or skewed shapes, in general just try to simplify as much as possible.

The textures must be in .png format and their resolution must be square and of power of two  (i.e: 128x128 or 256x256 or 512x512) the minimum resolution is 8x8 pixels, maximum 2048 (untested), generally recommend sticking to 512x512 as the maximum.

Limitations of JSRF's levels visual models

JSRF Level Visual models only support one UV per vertex, which means you have to treat the model so there aren't multiple UVs per vertex and you need to be very mindful about it, otherwise if you make a complex mesh and once compiled you see it in-game with messed up UVs, it might be tricky(in Blender) to find which part of the mesh is causing the issue.

Ok here's an example (the box in orange) of the issue and how it's solved:

Grind Paths

Grind paths can be created by extracting the edges of a mesh as curves, you then need to add them on the "GrindPaths" collection, inside it's own collection/group.

Also once you're done editing the grind path, make sure to do this for the curve objects:  Object >> Apply >> All transforms
Not ideal, but for now that'll be necessary.

To extract edges as a curve, you can use the following addon, note: in the script change the version from "blender": (2, 80, 0), to whatever version of Blender you're using so it loads up.
In blender you'll find the button while in Edit mode (edges) right click and at the bottom "Edges to curve"

Note: right now bezier or other types of curves are not supported, or at least I don't know Blender well enough to tell you which type of curves the exporter would support, so try starting from extracting edges as a curve with the add-on I just mentioned, unless you know a way to manually make "curves" that are just point to point without smoothing.

Part 2: to setup and compile the mission file(for custom spray can placement, player spawn location and death warps) see the tutorial on this link

 

JSRF Graffiti Tool - Fixed: Golden Rhino and Police graffitis missing

Hey there,

Just a quick fix for the JSRF Graffiti tool which wasn't listing the Golden Rhino nor Police graffitis before.

Click here to download the JSRF Graffiti Tool v1.0.0.5

JSRF modding tutorials

 Hey there, I am still working on the tools to create JSRF levels (nearly done) but I also have to prepare a tutorial, in the meantime here are some video tutorials on how to mod JSRF textures and models, thanks to YayoDeLaRiva and  Lkymn for making these tutorials:

 

JSRF - custom test level and messing around with the level physics

 Hey, short post, the other day we were on stream testing the level surfaces to see if we could make loops and whatnot, watch here:

https://www.twitch.tv/videos/1451203978

First JSRF Custom Level

 Hey there,

About a year ago I was trying to make custom levels for JSRF, I was able to build brand new visual models for the levels and compile the physics collision models too, but there was a part of the collision data I could not figure out, that needed to be calculated, and since it wasn't,  in the new level, you'd just fall through the floor and clip through everything.
So I sought help from others but we couldn't figure it out, at least not how we were trying, through binary/hexadecimal/statistical analysis.

So I recently reached out to Gurten (who made the amazing Blender character model/animation importer) and he figured out the collision mesh triangle data in less than two weeks 😮

His reverse engineer method is through disassembly, which means de-compiling the game's executable/program file aka turning the program's executable binary file into a (massive and convoluted) list of CPU instructions, then analyzing CPU instructions/functions to see how the game loads the files and how it processes the data, easier said than done though.

This technique definitely was the only way to reverse engineer this bit of data about the physics collision 3D meshes of JSRF and people who have the (dis)assembly reverse engineering skills, are hard to come by and they usually have better things to do, luckily Gurten was willing to take the time and help, and he did an amazing job.

Anyways here's the result of the first properly compiled JSRF level:

I may or may not make a blog post later on about the process of how I tried to reverse engineering the level collision data(and failed) + with other people, and finally how Gurten went about it and succeeded, but it'd be a pretty long blog post.

I didn't publish the second blog post part about "how I reverse engineered JSRF" because it quickly got too technical, long and would be boring and pedantic to the reader.
Perhaps I'll make a video with audio commentary and graphic animations explaining the reverse engineering process, the mod tool, and how it evolved over a decade.

Video format with audio would definitely be a more dynamic, concise and a fun format to watch rather than reading a long blog post, but again, it would be a lot of work creating such video, so we'll see.

For now, there's some more work to do on the tool and things to figure out about JSRF, on compiling levels, and also creating a level creator/editor tool to make it more accessible to create levels for JSRF.

JSRF ModTool 2.7 - model importing: fixed material groups corruption when adding/removing materials

 
Download the JSRF ModTool 2.7 here

Hey there, I have still been working on the JSRF tool, mostly reverse engineering and experimenting recompiling levels(aka 'Stage') data, such features are not accessible in the tool's interface yet, if you're a developer and want to try it, it's all in the code.

While we're close to being able to create custom levels, we're stuck on figuring out part of the level collision 3D mesh data.

I have managed to recompile a custom visual mesh for the level, as well as part of the collision mesh data, but since part of the collision mesh is still unknown/not understood and has to be calculated, right now we just fall/go through the collision mesh.

In the following video, it's a new compiled visual mesh, while maintaining the original Garage's collision meshes:

This post is also about the JSRF Tool 2.7, where I have fixed MDLB model importing, before, adding or removing material groups in the model(MDLB) importing interface, would corrupt the materials groups, giving wrong materials to the model.

It's finally fixed, if you're a developer and have been using/modifying the source yourself, I recommend checking out the GitHub repository where I might update the code, while I don't make blog posts about it: https://github.com/neodoso/JSRF_ModTool, otherwise here's the tool with the fixes:

Download the JSRF ModTool 2.7 here

JSRF speedruning tutorials, tips and tricks and more at www.jsrfspeedruns.com

Hi there, I thought I would share the wonderful www.jsrfspeedruns.com website made by people from the jsrf speedrunning and modding scene, they put a lot of effort into documenting all sorts of details about the game and they also created a complete guide to speedrunning JSRF with all the techniques, tricks, bugs, so if you're interested in upping your game on JSRF, trying speedruning or even just learn more about JSRF, www.jsrfspeedruns.com is the place to go.

 

JSRF ModTool: Open Source

Hey,

I am making the JSRF ModTool open source, I wanted to do this for a while but wasn't very confident about my code, either way its best to put it out there once and for all.

If you're a programmer and are interested in modifying the tool for personal use, or contributing, I am all for it, I am also all ears if you have feedback on my coding, bad practices etc I would love to hear it so I can improve.

Here's the GitHub page for the tool:
https://github.com/neodoso/JSRF_ModTool

 Cheers!

JSRF ModTool 2.6 - Model importing fixes

Hi, here's a new version of the tool with fixes for model importing.

 Download JSRF ModTool here

Changelog:
-Fixed support for new materials manually added when importing, before it would not load nor add the new materials to the imported model.

-Fixed UVs getting messed up when importing.

Tutorial: character model swapping

Hi there, here's how we can swap player models by almost any model, in this case we're going to take a non playable "enemy" model and paste it into a "player" (.dat) file.

First let's choose which model we're going to take, for instance go to the "Enemy" folder and open Armed.dat, then inside NORM[3] and select the first MDLB.

Under the dark grey bar with text "Armed.dat"click the "copy" button, now what is selected is copied to the clipboard memory.

Now on the list of folders and file(on the left) go to the "Player" folder and select the Beat.dat file.
Thenselect the first MDLB as in the following image:

Then click "paste"

We've pasted the MDLB from Armed.dat into a Beat.dat's MDLB.

You'll notice we also need to replace the texture, but first we're going to make some parts of the Beat model, invisible, such as the head and hands models, because the model we're replacing already has those parts integrated in the first model.

Here's how the contents of a player.dat file is structured:

Inside the NORM [13], go to each head and hand model (MDLB) and click "Collapse vertices", this button moves all the model's geometry points to the same position, making the model invisible.

If the player model you selected has "Jiggle" models(such as clothing, chains or hair that moves), you can remove those by selecting one and clicking the "empty" button, but using "empty" might cause the game to crash, as the game expects to find those model parts, it's original bone hierarchy and to apply animation or the "jiggle" effect.

So instead of using "empty" we use "collapse vertices" for the hands, head models and jiggle models.


Finally lets get the texture from the original model, copy and pasting within the JSRF Tool won't work for this, because the textures have a unique ID number, so instead we're going to replace the image data through an image editor so the texture ID is preserved as the original.

Load Enemy\Armed.dat, select the texture and click "Edit texture"

Now open Player\Beat.dat and select the second texture and click "Edit texture"

In your image editor, copy the texture of Armed.dat, into the window of Beat's texture, save and then go back to the JSRF Tool with the beat texture selected and click "save changes".

 

That's all!

And the result ingame: