Bring Sims 4 models to Tower Unite

Glossary

Some of the terms used can be a bit confusing or intimidating for beginners. Here's a list of some of them, and their meanings

Vertex - A single point in 3D space. A model is made up of many vertices, the plural term for vertex.

Edge - A line connecting two vertices together

Face - A flat plane between three or more edges.

Mesh - A collection of vertices, edges, and faces. A model can be made up of one or more meshes.

Model - The definition of model depends on who you ask. Sometimes people use it to mean the same as mesh, sometimes it's a collection of meshes, sometimes it's a mesh as well as its rig. To keep it simple, think of a model as "one or more meshes plus whatever else is needed to make them work"

Armature/Rig - Both terms mean the same thing here. It's a collection of "bones" - long rigid sticks that you can pose like action figures. Meshes are linked to these in order to be posed and animated. In order for this to work, the mesh also needs vertex groups with the same name as the bones.

Vertex Group - A collection of vertices. These are used to tell the model which vertices to move when a bone is moved. Vertices can be part of multiple groups; for instance the knee might be grouped to both the upper and lower leg, flexing between them as the character moves.

Vertex Weight - Each vertex in a Vertex Group also has a Weight in that group. It's used to determine how much to move the vertex by when the corresponding bone moves. Ideally it's in the range of 0 to 1, where 0 means "don't move at all when the bone moves" and 1 means "follow the bone anywhere it goes". (You can even go beyond this range. A value of 2 would move twice as much as the bone. Some games will normalize this back to a range of 0-1, however.)

Vector - To keep it simple, a vector is a mathematical "line" or "arrow" that is defined by having a length and a direction. The length is represented by a single number, and the direction is represented by three numbers, for the three dimensions we use in Blender. The proper name for the length is "magnitude", but they mean the same thing here.

Normalize - Take a number in a range of 0 to some maximum value, and squish it into the range of 0 to 1. For vectors, it usually means "make the vector a length of 1", which happens to be mathematically useful if you only care about a vector's direction.

Normal(s) - The direction that a vertex, edge, or face is pointing in. The name is based on the fact that it's a "normalized" vector - it doesn't need a length beyond 1, it just needs to point in a direction. The normals are mainly used to determine how an object is lit and shaded. Normals that are aligned can present a smoother surface, while misaligned normals can show up as hard edges.

Normal Map - A 2D texture containing normal information. Storing this in actual 3D geometry gets really heavy on the computer's memory and processor, so you can pre-calculate it into a 2D texture, called a normal map, and use that instead. The vanilla Sims 4 characters usually export with a normal map alongside them.

Backface - The backside of a face, as determined by its normal direction. Blender displays these by default, but games often will not. This is because they represent the inside parts of a model, and should ideally never be seen by the player, so they get hidden (or "culled") to save render time.