So after using the 3D Shields Package mod with a few other mods(HIP, Christian Immersion mod, and Legacy of Rome Expanded), i was able to find out what things rendered the features of this mod incompatible or incapable of working with them. In the case of the "Legacy of Rome Expanded" mod, it made modifications in the mapitems file that is primarily used by this mod for the shields. In the case of HIP and the Christian Immersion mod, both of them make modifications in the 00_religions file, something that this mod modifies in order to show frames that are dependent on the religion of a County, Kingdom, or Empire. Thus, any mod that features changes in the frames (ex: Legacy of Rome Expanded) or make modifications in the 00_religions file (ex: Christian Immersion Mod, Ancient Religions, HIP,) are going to be incompatible.


Fortunately, making the mod compatible is somewhat easy since it doesn't really change or add anything except for the frames. For mods that make changes to the mapitem file like "Legacy of Rome Expanded", simply deleting the mapitem file of that mod allows for the 3D Shields mod to work, though you have to be sure that said mapitem file isn't necessary to the features of the mod that you're trying to make compatible. For mods that make changes to the 00_religions file, you have to edit the file itself, changing what is written in the graphical_culture block.


In the HIP mod and Christian Immersion Mod, the Orthodox graphical_culture block looks something like this:
orthodox = {
graphical_culture = westerngfx
While in the 3D Shields Package mod, the Orthodox graphical_culture block looks something like this:
orthodox = {
graphical_culture = orthodoxgfx
The only thing you need to change in the 00_religions file is that specific part, changing what is in the graphical_culture block to its equivalent in the 3D Shields Package mod, do this for any of the graphical_culture block that is different in the 3D shields version, and for any added religions or heresies, use the parent religions graphical_culture like any Orthodox or Catholic heresy must use the "orthodoxgfx" and "westerngfx" respectively.


When making compatibility patches for other mods with the 3D Shields mod, don't make direct modifications or changes towards the Original files of the other mods, since it could potentially break said mods.