First Person Rendering with Panini Projection

In Satisfactory, like many FPS games, first-person equipment is drawn in a special manner to avoid several problems, such as ensuring the pioneer’s arms and tools don’t clip into the environment when you get really close to things.

To limit visual distortions when the user is playing with a large FOV, a vertex shader called a Panini Projection is applied to the world and the player’s first person models. To learn more about this technique, see this article, which was originally linked from Unreal Engine documentation page about a different unrelated implementation of the technique.

Satisfactory always renders the player’s first person viewmodels with a fixed 90° FOV, so it’s best to work on these meshes at a 90°. This will minimize errors and let you get the best idea for how it sits on the screen, even in a modeling program.

Note that in game option "First Person FOV Modifier" adjusts the model’s scale, not the Camera FOV. There may be some math done to the parameters fed to the Panini Projection, but if you hook up everything right you won’t need to worry!

You can tell a material is not set up properly if its position changes noticeably when the user adjusts their FOV.

The below screenshots showcase the appearance of ExampleMod’s example trinket at different "Field of View" game option values. The left side has the projection enabled, while the right side has it disabled.

Note that the model does not connect correctly when the projection is disabled at FOVs other than 90°.

A number of base game materials already have Panini Projection support built in. You can create material instances from them to easily enable the effect on your modded content assuming the materials' other behaviors suit your needs. It can be enabled via their material parameters, usually called something like "UsePaniniProjection". This is the approach taken by Example Mod’s Example Trinket, Desc_Trinket_TvOfKnowledge.

Examples of base game materials that support Panini Projection include equipment and trinket materials, as well as MM_FactoryBaked. For example, trinkets can use the Asset_Master material with the "UsePaniniProjection" option enabled.

Panini Projection can be integrated into custom materials in two main ways, depending on whether your material uses Material Attributes.

Use Material Instances to enable toggling the effect per-instance without recompiling the shader. This is particularly useful because the models of other players, and 3rd person view models or dropped items, should not have the effect applied.

For equipment items, you will probably need one instance with it on for first person, and one with it off for dropped items.