https://sims4studio.com/thread/134/mini-tutorial-sims-hair-components

This mini-tutorial will show you all the components of an EA hair. Most of these components need to be modified during the process of creating your own new hair mesh.

  1. This is the EA hair I will use as the example for this mini-tutorial.

  1. Each hair has 4 LOD meshes. LOD stands for level of detail. These meshes are displayed on the Sim according to how close the viewer is viewing the Sim from. At very close view LOD 0 is seen on the Sim. LOD 0 should be a high quality mesh able to stand up to close scrutiny.

LOD 1 is seen when the viewer is a short distance away from the Sim. EA usually reduces their poly count for this mesh but not by a whole lot. The viewer is still close enough to the Sim to see any obvious errors in the mesh.

LOD 2 and LOD 3 are seen when the Sim is viewed from so far away that only the most obvious details of the mesh will be seen. Here you can see a close up of the LOD 3 of this EA mesh. Note the obvious flaw that has resulted from a significant reduction in poly count on this mesh. This is ok though because the player will never see this mesh up close. It only shows up when you're zoomed so far from the Sim that this detail is impossible to see.

  1. Each EA hair style has "hat chop" meshes that are displayed on the Sim if the Sim has a hat on. EA uses these meshes to help keep poly count down and to keep hair from sticking out through the Sim's hat. In Blender you will find 3 meshes per hair.package. One is the main mesh and the other two are the hat chop meshes.

  1. This is the main mesh's 1st UV map. Note that it is situated on a much larger .dds image. This is the composite image that is used in the game to provide the texture for hair, skin, face, accesslories, and etc. You must place any new hair texture you want to use over the spot where EA has theirs placed and your hair map must fall in the limits of that space as well.