This is for modders who would like to create a custom overlay. The process is simple. Create overlay art and put it in the directory that matches a valid armor. Any Armor that uses the eyes biped slot is considered valid for overlays. The overlays are loaded at runtime by deriving unique file paths that are based on the armors own model path. An overlay file path may also be defined by the author when a derived file path is not suitable.


Create the art
The framework supports interface (swf) and texture (dds) files for art assets. There are some key differences between the two types so take some time to consider them. Take special care to draw your overlay art as what would be considered 100% opaque. This is because users may adjust an overlays alpha channel to their own preference using a slider control in MCM. If your overlay art is released with 50% opaqueness baked in the users won't be able to achieve 100% opaqueness if they prefer. 

A) Create a texture overlay 
Most authors are already familiar with `dds` texture files and tools like Paint.net or Adobe Photoshop. The process is straightforward when creating an overlay texture but lacks any of the advanced functionality of interface based overlays.

All overlay textures should use a size of at least 1920x1080 or greater. The texture format should be `DXT5 ARGB 8 bpp | interpolated alpha` with `Generate MIP maps`. When you are finished with your overlay save it as a '.dds' texture file. All texture overlays are loaded from the `Textures` folder.

B) Create an interface overlay
The interface `swf` files are vector based art which can be created in programs like InkScape, Adobe Illustrator, and Adobe Animate (Flash). Once the art is imported & published through Adobe Flash, the framework will load the interface `swf` files. The impressive thing about interface based overlays is that they support animation and filter effects. Interface based overlays are also capable of communicating with papyrus scripts.

Open Adobe Flash and create a new AS3 document with a size of 1280x720. The size of 1280x720 is the default resolution of the Fallout 4 user interface. The Fallout 4 user interface will automatically resize itself to the user's screen resolution. Don't worry about the low "resolution" though. Due to the nature of vector based graphics, the user interface is infinitely scalable without quality loss. 

If you prefer to design your vector based art in a program other than Adobe Flash, it is possible to import files from Adobe Illustrator, Inkscape, and others. In the Adobe Flash file menu select "Import" and choose "Import to Stage..." or "Import to Library...". Select a valid art file and add it to the stage.

When you are finished with your overlay publish it as a '.swf' file. All interface overlays are loaded from the `Interface` folder.


Add the overlay in game
There are a few ways of implementing an overlay in game. Take some time to consider the best one for your project.

A) Using an automatically derived file path
By default, the framework will assume a file path which is derived from the Armor's own model path. If the Armor object has both a male & female model path then an overlay path must be provided for both genders, even if they are the same. First the framework will read the relevant Armor model path and then generate several potential overlay paths automatically.

Let's take for example vanilla sunglasses which are equipped by a male player. The default model path for male sunglasses is "Meshes\Clothes\ShortSleeves\MGlasses.nif". The framework will attempt to find an overlay in order of the following file paths..

• ** See option B below.
• Interface\Clothes\ShortSleeves\MGlasses.swf
• Textures\Clothes\ShortSleeves\MGlasses.dds
  

• Texture overlays should not be packed into archives. Distribute overlay textures as loose files.
• Interface overlays are allowed to be packed into archives.
• Ultra widescreen support is untested at the time of writing. The theory is that it won't work for textures because the compression snips out anything outside of the set resolution.
• There is a known issue where the "OverlayMenu" is rendered on top of the "HUDMenu". This means an overlay could potentially obscure a menu element. As a temporary solution a mod user can make overlays semi-transparent. Track the issue here.