Koikatsu to EmotionCreators Porting Guide - IllusionMods/KK_Plugins GitHub Wiki
What you'll need:
SB3Utility
EmotionCreators runs on a different Unity version than Koikatsu which makes Koikatsu shaders unusable. To make a mod compatible with EmotionCreators, you'll need to remove Koikatsu shaders and replace them with EmotionCreators compatible shaders.
First, open the mod you want to convert using SB3Utility. Double click on of the animators and select a material. This hair accessory uses the Shader Forge/main_hair shader. You'll need to find a unity3d file in EmotionCreators with the same shader. This is a side hair accessory, you can find EmotionCreators side hairs at emotioncreators\abdata\chara\00bo_hair_s_00.unity3d.
Open that file as well. Click the materials tab and you will see the shaders listed there. Select Shader Forge/main_hair then click Assets->Mark/Unmark For Copying.
Switch back to your mod's unity3d file. Click the materials tab and find the shader. Select it and click Assets->Attention!->Remove to delete the shader. Then Assets->Paste All Marked. This will paste the EmotionCreators shader in to your Koikatsu mod. Note it also brings the Unlit/Texture shader with it, this is normal.
If you still have the animator open, click the refresh button. The material will now show an empty shader. Click the dropdown list and select the shader you just pasted it.
If you have many materials in your mod, double click all of them to open them. Open each one and select the new shader.
This mod also has the Shader Forge/main_item shader. After you've finished one shader, repeat the process for any other shaders, delete the Koikatsu one, copy in the EmotionCreators shader, and reassign them to any materials missing the shader.
Once finished, zip the mod back up and try it out. You can edit the manifest.xml of the mod and add <game>Koikatsu</game> to the Koikatsu version of the mod and <game>EmotionCreators</game> the the EmotionCreators version. This will mark the mod so that it can only be loaded on the specified game.
Hair accessories, as used in this example, do not use NormalMap textures, but many other things including accessories and clothing do. EmotionCreators uses a slightly different style of NormalMap textures, see the NormalMap Editing Guide for how to convert those for use in EC.