Attachment System Components
The character pipeline uses an attachment system to customize the appearance of the character model in a variety of ways. In general this allows you to choose different skins and accessories in order to create a unique look.
In CRYENGINE, four attachment types are supported:
1- Skinned Attachment and Skeleton-Extensions
With skinned attachments, entire body parts such as heads, hands, or upper & lower body parts can be replaced. Furthermore these parts are automatically animated and deformed by the base skeleton. With the older version of CRYENGINE it was only possible to attach a new skin if every joint already existed and was available in the base skeleton. However, since CRYENGINE3.6 we have supported a new feature called Skeleton-Extensions that allows the use of skinned attachments that have more joints and different joints then the base skeleton. It is also possible to merge all types of skeletons together, even skeletons from totally different characters.
2- Joint Attachment
Joint attachments provide a socket in which you can optionally place a model, a light or another entity. Sockets are linked to a joint and move with the joint when the skeleton is animated. Since CRYENGINE3.6 secondary animations can be enabled on a socket, these are additional motions based on a physical simulation and are generated in response to the movements of the character to make loosely attached objects behave more realistically when the character is undertaking fast movements. These secondary animations can also be redirected to the skeleton of the character itself and apply the simulated motion to all vertices that are part of the skinned mesh and weighted to the joint (this is very useful when animating hair and cloth). By enabling collision detection, these simulated objects can also interact with the character.
3- Face Attachment
Face attachments provide a socket in which you can optionally place a model, a light or another entity. The socket of a face attachment is attached to one particular triangle (=face) on the surface of the mesh and moves along with the triangle when the skeleton is animated and the mesh gets deformed. The location of the face attachment can be relative to the triangle and it is possible to assign face attachments to all skinned meshes of a character.
4- Proxy Attachment
To deal with collision detection and response on living characters, a special geometric object called a lozenge is used. Lozenges are normal attachments that are linked to the joints and move with the skeleton. A lozenge is represented by four numbers, and with these four numbers, points, spheres, capsules, line-segments, rectangles, boxes, 2D-lozenges and 3D-lozenges can be created. That’s eight different shapes (and everything in between) that can be used to approximate the shape of arms, legs and the torso of a human body.