GRF Editing Basics

This guide will go over the basics of editing the RO client's data.grf file on a personal level.

Tools

First off, you'll want a GRF editing tool. There are several options which can be found at RateMyServer's tool download page:

• GRF Factory: An older GRF editing tool. It does all the basic things you'd need, but it is not the most time efficient as it lacks any kind of directory sorting and must fully repack the GRF to complete any changes.

• GRF Tool: More up-to-date then GRF Factory, allowing viewing of directories and better filtering.

• GRF Builder: The latest GRF editor. A noteworthy program due to its ability to merge files and repack GRFs via re-arrangement instead of re-compressing the entire file, greatly reducing the time required to implement changes.

Given the options, GRF Builder is the tool of choice due to its capabilities compared to the others. The only downside of GRF Builder is that it doesn't yet have the ability to preview spr files. This guide will be using GRF Builder.

Finding your desired files

Before you can begin editing the grf, you'll want to know what files you're editing and where they're located in the grf's directory. Figuring this out may take some time, as a number of RO's files are named in Korean, especially when it comes to graphics. (Attached is ClassSpriteLocation.png, which shows what is contained within some of the folders in the sprite directory.)

Extracting a portion of the grf by filtering file types, then searching through those is always an option. (Something to note is that some files come in sets of different file types, such as sprite graphics using both spr and act files, or maps using gat, gnd, and rsw file types.) Doing so will create a folder named "data" in the same directory as the grf file, containing all the extracted files.

If you're doing repeated editing, it may be useful to keep a master set of extracted files that is used only for referencing. This also means you have the original files in case the need arises to revert changes that did not work.

Adding your changes to the grf

1. Create a directory containing your desired files, that is exactly the same as the directory in the data.grf, starting with a folder named "data".
2. Open data.grf with GRF Builder.
3. Click Merge dir and select the "data" folder created in step 1.
4. Click Repack.

You will need to create a directory in your computer that exactly matches the directory in the grf file, and place the edited files into this directory. For example, if you were replacing the spr and act files for a Kafra, you'd need to create a directory of folders named "data"->"sprite"->"npc", and put your edited files in the "npc" folder. (Attached is DirectoryExample.png which shows this.) This folder named "data" can be put anywhere on your computer, wherever is convenient for you.

If you extracted files from the grf, the editor tool will have created these directories for every file that you extracted. You can use this, though there may be other files here that you didn't change as well, which won't have any affect other then increasing the time necessary to put the files back into the grf.

Alternate Method: Turning your edits into patches for repeated use

Creating the patch grf/gpf:
1. Create a directory containing your desired files, that is exactly the same as the directory in the data.grf, starting with a folder named "data".
2. In GRF Builder, click New and type a name for the patch.
3. Click Merge dir and select the "data" folder created in step 1.
4. Click Repack, then click Close.

Applying the patch grf/gpf:
1. Open data.grf with GRF Builder.
2. Click Merge GRF and select the patch grf/gpf.
3. Click Repack.

Instead of directly placing the edited files into the data.grf, another option is to create new grf files containing only the edits, then merge them into the data.grf. The advantage of this method is that you can save these small grfs and easily re-use them, useful if you have edits that you want to be able to add and remove. (In order to remove an edit, you overwrite the edited files with the originals.)