Hello and welcome to my first guide where I will teach you how to properly upload your addon easily on the Steam Workshop for Garry's Mod!
I will be uploading my map Garry's Mod | Battle Royal city but you can do it for custom weapons, model, NPC, etc...

If you encounter any problem while you publish your addon, feel free to comment on your problem in the comment with, if possible, the log from GMPublish, I will usually answer in under a day!




PS: If you want to download my map, click here and if you like my work why not sub to my Steam Workshop page here

• No offensive comment!
  
• Any structured criticism is welcome!
  
• Be cool and nice to everyone, even if a person is not
  
• Avoid copy/paste messages, please.
  
• You can self-advertize your addon on the comment but no copy/paste(Do not advertise the same addon twice)!
  
• Steam Rules and Guidelines

If you do not follow the rules, your comment may be deleted.

GMPU is a tool allowing through a simple interface, to create GMA files (used by Garry's mod to simplify addon processing). It also allows you to upload this GMA file to the Steam server under your account to publish your addon to the Workshop! Don't worry, it's safe and easy to use if you know what you're doing!

GMPU can be downloaded through this Source Forge page[sourceforge.net]

After the download is finished, you will have a compressed file. Just extract it in a folder wherver you want, you can now use gmpu! (Not really, we must configurte it to work with your Steam account...)

To configure GMPU, simply open the .jar file, you will have this kind of window popping up on your screen! Don't worry, your UI may be a little bit different. Don't worry, it's the same version and I only have my maps already register in the list above, yours will be empty.
Now, let's configure GMPU by clicking the settings button in the bottom left corner of the windows!
A new smaller window will pop up. Click on the last button "Set Paths".
ANOTHER window will appear. Here, just go to your Garry's Mod bin directory and select gmpublish.exe for the first one and gmad for the second one as such:











Now click OK! You have successfully configure gmpu!

Before we can use GMPU, we have some prep work to do first!
I usually work by doing a folder on my desktop (the location doesn't really matter as long as it's easy for you to reach.)
The name of the folder doesn't really matter much as well, just don't make it too long, no special character, no spaces, etc..

Here is my folder on my desktop! In it, I've recreated Garry's mod garrysmod layout folder.
So I've got a maps folder, a materials folder, as well as a model folder.
If you upload sound, you would put the sounds folder with your file, if you publish scripts, you would put your script in the lua folder, etc...
This process is important as it's the step most people miss and fail. Recreating a perfect folder layout as garrysmod is important!

SOME FILES ARE BLACKLISTED, you can't publish whatever you want. You can only publish .bsp, .mdl, .phy, .vtx, .vmt, .vtf, .wav, .png(for the map thumbnail in Garry's mod) etc... If you try to
upload a file not recognized by the source engine / Garry's Mod, GMPU will return an error in the log section.

When you have fully recreated the garrysmod layout with all your files in the correct folder, we can start creating a GMA file and upload it to Steam server.

If you are not uploading a map, you can skip this step!
IF YOU ARE PUBLISHING A MAP, PLEASE, DO NOT SKIP THIS STEP!

A lot of mappers publish a map without a thumb image. So, when people download their map, you find the usual map name without a thumbnail in Garry's Mod which is annoying and would simplify map selection for players.
To create a thumb for your map, create an image 128x128. Put whatever image you want (an image from your map would be preferable...)
When you're finished, export your file as a .png file in the: maps>thumb folder.
As you can see, I've got a thumbnail for my map, 128x128 .png in the maps>thumb folder.

Now, when people will be searching for your map, they will find it more easily on the map list and they will be happy!

Before uploading your file to the Steam workshop, you must create a GMA file. To simplify a lot a .GMA file is like a .RAR or .ZIP file with your addon files.
Thanks to this file, Garry's mod will have a better time managing addon and it's lighter for Steam's folder than to have hundreds of folders.
To create a .GMA file, open GMPU if it's not open already, and select create .GMA in the upper radio buttons selection.
As you can see in the image above, choose the folder you have made with all your files with the folder button. You must select the root folder you have created and not the maps / materials / models / ... folder.
Select the different tags for your addon. Here, I chose Maps then Fun and Roleplay. These are used in the Steam workshop research engine!
Then, for the .GMA output, select where you find to generate your .GMA file and what name it will have. As always, no spaces, no special characters, not too long, etc...

When you are done completing all sections, click the "Add to Queue" button. You will have a new entry in the table on your right. Select it by clicking on the line and click on the button "Execute!"
If everything is good, you will have written "Done!" in the status column.


If you don't have "Done!" Written, fell free to share your log in the comment, I will try to help you find the problem!
If you have "Done!" this process, go in your .GMA output location to make sure a .GMA file has been created! If so, you can go to the next step without a problem.

If you encounter a problem during this step you can try this tips before going on forums or in the comment section below, maybe you have just a little problem not worth wasting your time troubleshooting the problem.

• Make sure you don't have spaces, special characters in all your files/folders names. Also, make sure that your map name is under 30 characters including the .BSP part!
  
• Make sure you haven't got any blacklisted files. You can easily check for this error inside the log box on the right. You will have a line saying something like "folder/file
  [Not allowed by whitelist]"
  
• Make sure you have selected the root folder and not the models / maps / materials / ... folder when selecting your folder.

If any of these tips have helped you, comment down below the log and every possible information you can for us to help you :)

Congratulation! You have done most of the work by now. We just have to upload your .GMA file on Steam's server and you will have a new workshop item on your list!
To do so, change your selection from "Create GMA" to "Create" on the radio button selection.
Change your folder selection for a file one and select your .GMA file!
Select a 512x512 JPEG image for your item's thumbnail. Load it by clicking the "Load" button and by selecting your image!


This image is really a pain in the youknowwhere! The image MUST BE a .JPEG and not a .JPG
If you chose a .JPG file format, GMPU will crash the creation process! I can't say it enough, It must be a .JPEG and not a .JPG file format
If you get the same error message I got, just change the extension of your file on paint to a .JPEG format!

When you have completed each section, click on "Add to Queue" and then on "Execute". BEFORE YOU EXECUTE, remove the Create GMA Action, let's not confuse GMPU even if you shouldn't have any problems by not removing the Create GMA action.

You should now have a new entry in your Workshop item list!
If you have encountered any problem, you can ask them in the comment.

If you have found one or more section of this guide isn't clear and if you didn't understand something, tell me in the comment as well, I will answer your question(s) and try clearing up the guide!

Again, if you liked this guide, please,

If you want to download my map, click here and if you like my work why not sub to my Steam Workshop page here

Agur,
Ttiki.

• No offensive comment!
  
• Any structured criticism is welcome!
  
• Be cool and nice to everyone.
  
• Avoid copy/paste messages, please.
  
• Steam Rules and Guidelines

If you do not follow the rules, your comment may be deleted.

https://gtm.you1.cn/id/Ttiki/