Legacy Reference

Secondary Animations (Simulations)

You can also use sockets to produce realistic movements of joint and face attachments. This type of animation is always a reaction to a primary (character) animation, and are called secondary animations or motion simulations. Such animations can simulate the movement of attached static objects such as weapons and holsters, muscles, and fat.

In addition, it is also possible to create complex setups to simulate the motions of swinging hair braids, tentacles, chains, ropes, necklaces, clothing, and other loose or dangling objects on a character. Chains can have branching strings and different physical properties for each link.

However, such motions are just approximations of real-word physical movements. In Lumberyard, the physical properties of springs and pendula are used to approximate (simulate) the physical movement of dangling or swinging objects attached to characters.

  • Pendulum: A bob connected to a rigid rod that experiences simple harmonic motion as it swings back and forth. The equilibrium position of an unconstrained pendulum is hanging directly downward. The swing is specified by physical parameters such as stiffness and stiffness target, and movement is constrained by cone, half cone, or hinge plane bounding volumes.

  • Spring Ellipsoid: A bob connected to an elastic rod. Unlike a helical spring, a spring ellipsoid can stretch in any direction. The movement of the spring is constrained to by sphere, ellipsoid, half sphere, flat plane, or line bounding volumes.

Moving springs and pendula have different motion bounding volumes that constrain the movement of objects attached to characters.

While the type, size, and shape of the attachment has no impact on its actual motions, it does determine which type of simulation is selected as the movements of a corresponding real-world physical object must be simulated. In this way, the socket and attached object realistically react to the movements of the character.

In addition, because moving attachments may collide with the character, this must be accounted for. For more information, see Proxy (Collision) Attachments and Collision Detection and Response.