PRISM Mod Creation Tutorial

[DigitalLove1010]

This post will hopefully simplify some of the processes required for modifying meshes and textures in Venus Vacation PRISM. Pretty much all of the techniques you will find here were implemented by @minazuki, @xenodoax and @fitzgerald4. I will try to keep this post updated as new techniques are discovered. 

 

It is not meant for those just wanting to install mods. @minazuki has created a few mods already which you can easily install to your game from this thread. I'm hoping to make a separate post for players to find and install mods in the future.

 

Preamble

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The current state of modding this game in these early stages is quite tedious and requires quite a lot of external tools. Once you have everything downloaded and understand the process it is much easier to implement new mods. This post's purpose is to try and simplify the steps for other modders.

 

Please bear in mind that modders are learning to utilise and create new tools all of the time so some of this information may end up being redundant or much easier to implement in the future. I will try to keep this post updated as much as possible.

 

Are nude models currently possible?

Check out the main modding thread for updates into this. For now the answer is no, we are still trying to build upon the base models. Until we understand how the weight system works in the game's engine we most likely won't be able to modify the character body meshes properly. @xenodoax and others are currently looking into this so if you think you can help please post on there.

 

What mods are currently possible?

You can edit any mesh or texture found in the game using this guide. You will need to have some basic knowledge of editing model meshes and textures. There are some limitations to the mesh editing process. We are noticing seams in certain areas of modded meshes which is likely due to the way in which they are being re-imported into the game.

 

Key File Types

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Common file types such as fbx and dds are not found within the file structure of PRISM. You will need to convert files using external tools and then convert them back in order to modify the game.

 

fdata

Koei Tecmo games use fdata files to manage game contents. Basically almost all game files are stored in this format. You can think of them as if they were zip files containing the data.

 

g1m

g1m files are model/mesh files which can be found when dumping fdata. These files can be converted for use in model editors such as Blender.

 

g1t

g1t is similar to g1m but holds the textures. These can be converted to dds for use in image editors such as Paint.net or Gimp.

 

Dumping fdata

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Go to your PRISM file installation folder (you can find this via Steam).

 

 

It is recommend that you create a backup of your installation folder in case anything goes wrong during the mod installation process, otherwise you'll have to download and reinstall the entire game from Steam. If you don't have enough space you should at the very least make a backup of root.rdx and root.rdb found in the folder fdata_package as these are the files that will be modified once you create mods.

 

It’s recommended to have a separate folder for creating and testing mods as well to keep all your tools together. Call it something like Prism Modding and keep everything in there.

 

fdata_dump.exe

DeathChaos25 has created this tool for dumping fdata. Download fdata_dump_1.5.0.7z then extract it to Prism Modding folder using 7Zip.

 

Go to folder Prism Modding\fdata_dump_1.5.0\net6.0. In folder Venus Vacation PRISM - DEAD OR ALIVE Xtreme – there is another folder called fdata_package. Drag this folder onto fdata_dump.exe. The program will start extracting the game's contents. This can take some time but we will eventually get a folder called fdata_out containing the files.

 

Viewing dumped Files with Noesis

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Download noesisv4474.zip here. It is a program for viewing and exporting the game files. You can unzip the folder to Prism Modding folder if you want or keep it in your program files. You will also need to download this plugin by Joschuka called ProjectG1M.zip in order to view G1M and G1T files in Noesis. Unzip and move ProjectG1M.dll to noesisv4474\plugins.

 

Run Noesis.exe to browse files. There are two key folders in this file structure: CharacterEditor/g1m for meshes and MaterialEditor/g1t for textures.

 

Although not all key models and textures have been documented, you can sort the files by file size which should give some indication of the more detailed files such as character costumes and textures. (It is known that skin textures are ~2049 KB, so sort by size and start browsing there).

 

 

You may also want to associate .g1m files with Noesis so that they open in the program. Right click any g1m file and click Properties, then change Opens with to Noesis.exe.

 

Exporting Meshes For Editing

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For the purposes of showing the process of editing a mesh, we will use Misaki's starter costume which has the file name 231e1f12.g1m. First, we need to convert this file into a format we can use within Blender. Copy 231e1f12.g1m to a new folder in Prism Modding, something like: Prism Modding/My Mods/Misaki Test Edit.

 

g1m_export_meshes.py

Download g1m_exporter_v1.3.15.zip by eArmada8 here. Extract this zip to Prism Modding and copy and paste to the Misaki Test Edit folder:

• g1m_export_meshes.py

• g1m_import_meshes.py

• lib_fmtibvb.py

 

It might go without saying but you'll need Python to run these scripts and pyquaternion is required for this script to work (Google how to “pip install package for python”). g1m_exporter_v1.3.14 conveniently comes with a .bat file to install this if needed.

 

Run g1m_export_meshes.py to generate a new folder with the name of the g1m file.

 

Blender Editing

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You will need this Blender plugin by DarkStarSword to import and export the generated files. Download or copy and paste the code and save as .py on your machine. Then, install it the same as any other Blender plugin (Edit/ Preferences/ Add-ons/Install).

 

Setup a new Blender file and delete any default objects in the scene. Click File/ Import/ 3dmigoto raw buffers (.vb / .ib). Select and import every file in the folder g1m_export_meshes.py created.

 

We finally have a working costume mesh in Blender which means we can edit any part we want. You may want to save a copy of this .blend file before making any changes so you can keep the base file.

 

To keep things simple, we'll just remove the stars on this costume. Each model seems to be split into many different parts so select the parts you want to edit, in this case its

• 18.vb

• 19.vb

• 20.vb

 

We can quite easily remove the stars in Edit Mode using Face select (use CTRL + L to select the linked area of each star for deletion).

 

 

You may have noticed that this file has duplicated meshes for this shirt. We believe this is due to handling the inverted normals (meshes facing toward the character) of the model. This duplication is done for the textures of the model as well. In this case we have 18.vb, 19.vb and 20.vb with duplicates 33.vb, 34.vb and 35.vb. I've found that these do not need to be edited and repacked for the mod to take effect as long as 18, 19 and 20 have been edited. To play it safe, it might be best to apply the edits to the duplicates too.

 

Exporting the individual meshes

You'll need to export all edited .vb files individually due to the nature of the Blender plugin. Start with 18.vb by selecting it in the Outliner then click File/ Export/ 3dmigoto raw buffers (.vb / .ib). Keep each file name the same as it was before (18.vb) and overwrite the existing file in the 231e1f12 folder. Repeat this step for the rest of the edited vbs.

 

Converting Meshes back to g1m

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Now that we have our edited meshes ready, we need to convert the files back to 231e1f12.g1m. Simply run g1m_import_meshes.py, this will overwrite 231e1f12.g1m with the new meshes and create a 231e1f12.g1m.bak automatically. This backup is your vanilla .g1m if no other modifications have been made at this point.

 

Converting the g1m File Back to fdata

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Download Atelier Yumia fdata mod toolset by eArmada8 here. Put a copy of yumia_mod_write_yumiamod_json.py in Venus Vacation PRISM - DEAD OR ALIVE Xtreme -\fdata_package.

 

@xenodoax has made a new Python script that will help us with the step. Download generate_yumia_mod_json.zip. Place both of the scripts into Venus Vacation PRISM - DEAD OR ALIVE Xtreme -\fdata_package.

 

We will need to make an adjustment to generate_yumia_mod_json.py so open it in a text editor or VS and change this file path to your copy of the game.

 

 

Run generate_yumia_mod_json.py. Enter your model name (231e1f12), then enter 2 as the file type (g1m). This will generate two new scripts: 231e1f12.file_metadata.json and a yumiamod.json file. A random hex value for the yumiamod.json file will be generated by the script, in my case its called 0x4b96cba5.yumiamod.json. Place both of these files in Prism Modding/My Mods/Misaki Test Edit.

 

In your yumia_fdata_tools-main folder there are a couple more scripts we need to place in the Misaki Test Edit folder: yumia_mod_lib.py and yumia_mod_write_fdata_files.py.

 

Run yumia_mod_write_fdata_files.py. It will take your modified g1m file, examine 0x4b96cba5.yumiamod.json and create a new file: 0x4b96cba5.fdata.

 

Packaging and Testing the Mod

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We finally have everything we need to test the mod in game. You need 4 files in your folder when releasing your mod:

1. The fdata package

2. yumiamod.json

3. yumia_mod_insert_into_rdb.py

4. yumia_mod_lib.py

 

 

Put these files in your game directory fdata_package folder, run yumia_mod_insert_into_rdb.py. The files root.rdb and root.rdx will be updated with your modified fdata.

 

Now we can test the mod. If your game is crashing that means there is a problem with your mod and you can restore root.rdb and root.rdx from a backup to make it work again.

 

 

Modding Textures

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We'll carry on using Misaki's default outfit for editing textures in this tutorial.

 

get_g1t_files_for_given_g1m

First we need to find the texture files we need. Another script by @xenodoax/@doctor science will be useful for this, download it here. We'll need another dump containing xml data which @doctor_science has posted here. Unzip the xml dump to your Prism Modding folder.

 

Edit get_g1t_files_for_given_g1m 1.1.py, you'll need to set the file paths for the xml data we downloaded as well as the folder leading to fdata_out.

 

 

Run get_g1t_files_for_given_g1m 1.1.py. Give it the name of the g1m file (231e1f12). This creates a new folder called copies containing all the g1t files associated with the g1m file.

 

Browsing through these with Noesis, I can see the texture I want to edit: 612db326.g1t. However, as you will recall from the mesh modding section, there are two files that are identical for the front and back faces of the mesh. The copied texture is called c2757cfe.g1t.

 

Let’s make a new folder in Prism Modding/My Mods/Misaki Test Edit called Textures. Create a folder in Textures called Original Files, place 612db326.g1t and 612db326.g1t here.

 

qg1t_tool

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We need a tool to repackage edited textures back to g1t format. Download g1t_tools_0.3.zip posted by @vagonumero13 here. Unzip in Prism Modding. Run Prism Modding\g1t_tools_0.3\qg1t_tool\qg1t_tool.exe. You should also associate g1t files to open with this program.

 

Let’s open 612db326.g1t first. At the bottom press Extract to save as dds.

 

Paint.NET Editing

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We will be using Paint.NET for exporting the edited dds file. Paint.NET has the correct output settings we need for exporting the image. For this edit I've done a simple color change for the entire texture.

 

 

Save the image as dds, call it something like 32370e2c_Edited.dds. The settings require that we use BC7 as the DX format.

 

 

Converting the dds File Back to g1t

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With 612db326.g1t open in qg1t_tool, click Replace (browse) and select 32370e2c_Edited.dds. We can do this again for c2757cfe.g1t.

 

Converting the g1t File Back to fdata

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We can now follow the steps we learned in the mesh modding section to convert the file back to fdata using yumia_fdata_tools. Remember you will have to use generate_yumia_mod_json.py for both 612db326.g1t and c2757cfe.g1t.

 

 

Combining multiple g1t and g1m Files

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Instead of having fdata for all 3 of our modified files, we can combine them into one when using yumia_mod_write_fdata_files.py. I have generated a new yumiamod.json file with the hex value 0x9c880972.

As long as we have _metadata.json files for each of the modded files, we can edit 0x9c880972.yumiamod.json so it looks like this...

 

 

 

Edited April 14, 2025 by DigitalLove1010
formatting

[xenodoax]

Great job @DigitalLove1010 putting this all together. This should help a lot of folks get caught up, but still a lot of work to be done.

[Maximumsily]

Hello. Is it possible to add font replacement support?
The .g1n file.
Thanks

[TamanScabies]

Hi, can you share the default Misaki costume model for me to open in Blender?

[fafaffadd]

When I try to import it into Blender, I get the following error. How can I fix it? Blender version I’m using is 4.5, but the same error also occurred in other versions.