How to Create Custom Assets

Information for people who want to learn how to create their own custom assets.

Custom AI

Information about how to create and manage custom AI variants.

Custom AI

Creating Custom AI - decls

This is an ADVANCED GUIDE. You are expected to have a decent understanding of decls, textures, and entities.

See the Following Books Before Proceeding


For starters, do all of your editing on an existing AI, so you know what the results will look like before you spend a large sum of time managing an entirely new AI variant.

For your custom AI, you want to copy all the decl files that will be changed. The entitydef file is the most important and mandatory for almost all custom AI. Paste the vanilla decls into a resource patch with a very high priority. Patch priority changes between each update, so you will most likely need to change it after each update. As of Update 6.66, e4m2_swamp_patch1 is a great patch to use.

Be sure to rename the decls too, so they do not replace properties of the vanilla AI.

After making changes to the decls, you will need to link them to the other modified decls if necessary. Make sure to do so for all of the modified decls. For example, to link the demon's FX, go to the entitydef file and change:
fxDecl = "character/stonegargoyle/gargoyle";
fxDecl = "character/stonegargoyle/stonegargoyle";

The stonegargoyle FX decl is a modification to the vanilla gargoyle decl.

For every added asset, you will need to add them to the EternalMod\assetsinfo JSON file. This must be done in BOTH the directory that contains all the added decls AND the level patch that holds your entities file(s). More info on this soon.

After everything is linked, move on to the level that you want to spawn your new custom AI.

Custom AI

Creating Custom AI - entities

See Creating Custom AI - decls before proceeding

idAI2 - Reference

Reference the original idAI2 file for the vanilla AI and copy it into a separate text file. Like the the entitydef decl file, this links all the decls together in a usable format. You will need to copy all of the decl references in this entity, just like for the entitydef file.

materialRemap is used to apply the custom textures to the new demon. Under renderModelInfo, a materialRemap parameter can be added (if it does not already exist). The following is an example.

renderModelInfo = {
	model = "md6def/characters/monsters/gargoyle/base/gargoyle.md6"; // base gargoyle model to use
	materialRemap = {
		num = 2;
		item[0] = {
			from = "models/monsters/gargoyle/gargoyle"; // replace existing texture
			to = "models/customization/monsters/mancubus/set12/mancubus_guns_set12"; // to this
		item[1] = {
			from = "models/monsters/gargoyle/gargoyle_body";
			to = "models/customization/monsters/mancubus/set12/mancubus_body_set12";

Notice that the set12 skin for the the Mancubus is used. See Creating Custom AI - textures for more information.

idTarget_Spawn - Reference

The idTarget_Spawn entity is used to spawn the custom AI. You will need more per custom AI that you want to spawn. Make sure to change the spawn positions for each. Always reference the idAI2 entity when spawning the custom AI, so you would not accidentally spawn the vanilla AI.


The process of getting custom AI working is a rather challenging task. You are bound to encounter some issues. Double check all of your modified decls and reference them with their vanilla counterparts. Same applies to entities. Ask yourself the following:

If not, check the idAI2 and idTarget_Spawn for typos. The encounter manager can also have syntax errors.

If not, check the materialRemaps or TGA files for typos. Also, check if the textures are added correctly in the assetsinfo JSON file.

If not, check the decls for typos or mislinks. The entitydef file might be the root of your problems if there is a mislink.

Double check BOTH assetsinfo JSON files for typos. Most crashes occur from syntax errors.

See Also

Custom AI

Creating Custom AI - textures

See Creating Custom AI - decls before proceeding

Creating Custom Textures

While adding custom textures into the game is possible, it is not the optimal choice. Even if the added textures are in a relatively high patch directory, there is the chance that some of them will not load properly, especially if there are a lot of added assets in the mod(s).

Instead, it is recommended to replace the textures of an existing playable demon skin. Since injecting gameplay-altering mods disable Battlemode entirely, there is little concern for distorting playable demon skins. You will want to edit the regular demon skin like normal and replace its name with the cosmetic skin that you want to replace. Make sure to include the ENTIRE file extension ( ex: mancubus_body_set12.tga$streamed$mtlkind=albedo )

Also, be sure to replace ONLY the matching $streamed$ TGA extension. In the case of Gargoyles, replace any .tga$streamed$mtlkind=albedo file with that of the same extension for a set12 mancubus skin, for example. Most cosmetic skins are located in warehouse\models\customization\monsters

If your extracted textures do not have the $streamed$ TGA extension, then reference here - Resource Data

See Also

Moving Assets

Information about moving assets from and to other patches.

Moving Assets

Assets Info Redirect Links

assetsinfo JSON

Format Overview
Reference: "resources" Array