Simply extend Ragnarok Online.
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This is SimpleROHook updated to work with 2018-03-28ragexe from iRO RE:Start. It may also support current (Renewal?) clients from other servers.

I have only tested the Bowling Bash gutterline and M2E functionality; judging by the logging console, some other stuff is definitely still wrong.

This fork also updates the project to Visual Studio 2015 (+ runtime).

Special thanks to @phaicm for the old default M2E configuration and @Toxetic for previously providing trusted binaries and the new default M2E config!

The best place to get technical support and be notified of updates is #addon-support on iROWiki's Discord.


  • Install the Visual C++ 2015 Redistributable (32-bit version, vc_redist.x86.exe, even with 64-bit Windows) if you don't have it. If SimpleROHook shows you a "LoadLibrary failed" error, it's likely because you didn't do this.
  • Download the latest build at and extract the archive somewhere.
    • You need "", not the source code.
  • Run SimpleROHookCS.exe
    • Only clients started after SimpleROHook will be affected. You'll get a logging console for previously started ones, but no actual functionality.
  • Right click the SimpleROHook icon in the system tray.
  • Uncheck Window > NPC Logger as it's useless.
  • Check 3D Map Grid > Show BBE to show gutterlines.
  • The display is a little glitchy on uneven terrain. Adjusting 3D Map Grid > Ground Z Bias can help.
  • 3D Map Grid > Alpha Level controls the opacity of the gutterline overlay.
  • Feel free to close the console window that pops up when you run a client.


  • To update, just replace the files in your existing SimpleROHook installation with the files from the new archive.
  • If you want to keep your settings, do not replace config.ini or config.xml!

Ground skill effect display (M2E)

  • Check 3D Map Grid > Show M2E to mark cells currently affected by ground targeting skills (Storm Gust etc.).
  • You can edit config.ini to set colors for specific skills.

New: Custom colors for deadcell/chatscope/castrange/gutterlines

  • Since Apr 11, 2018 you can change colors for the other features.
  • Edit config.ini as with M2E, you'll find a new [MiscColor] section at the top.
  • If you're updating from a previous version and would like to keep your M2E settings, this is the section you need to add to the top or bottom of the file:
    • Do not just add it somewhere in the middle, that would break all following M2E skill colors!
; Alpha is ignored for these - use the alpha level option in the GUI


I did the minimum work necessary to make Bowling Bash gutterline display work on the client mentioned above, with only a few minutes of testing. If this ends up crashing your client, I'd appreciate a heads up, but don't yell at me if that loses you an MvP or something.

As of September 24, 2017, iRO's GM team appears to tolerate gutterline and ground skill target display client edits. Keep in mind they may change their stance at any time and this doesn't necessarily apply to other servers. Whatever you do, use this tool at your own responsibility.

Build instructions (for developers)

  • Install the August 2007 DirectX SDK. Other versions will not work.
    • Note this will overwrite your DXSDK_DIR environment variable. If you've had the June 2010 SDK installed before, you'll probably want to set it back.
    • Set DXSDK_AUG07_DIR to the August 2007 DirectX SDK directory, e.g. C:\Program Files (x86)\Microsoft DirectX SDK (August 2007).
  • Clone the repository.
  • Open in Visual Studio 2015 (may also work in 2017, untested).
  • Select Release-iRO/Mixed Platforms build configuration.
  • Build Solution.

Original README


Simply extend Ragnarok Online.
For example, display font on client screen,it can placed easily in 3D map.

Copyright (C) 2014 redcat Lab. All rights reserved.


SimpleROHook is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <>.