zFiber ------ The zFiber node is used to convert a generic tissue to a "muscle" by adding a fiber field. The fiber field is a user-specified vector field through the volume of the tissue that defines the direction that the muscle will contract. +--------------------------+--------------------------------------------------------------------------------+ | Attribute | Meaning | | | | +==========================+================================================================================+ | **envelope** | Attenuates the excitation of this fiber node. | +--------------------------+--------------------------------------------------------------------------------+ | **strength** | Defines the strength of the muscle. This is similar to the Young’s modulus | | | parameter on the material node. | | | The unit for muscle force is: N/m^2 (Newtons divided by meters squared). | +--------------------------+--------------------------------------------------------------------------------+ | **strengthExp** | The power to which the value of the strength is raised. | +--------------------------+--------------------------------------------------------------------------------+ | **contractionLimit** | The muscle’s contraction force works to make the muscle this fraction of its | | | initial length. If this is set to 0.0, the muscle will seek to collapse into | | | nothing. If this is 0.5, the muscle will seek to be half its initial length. If| | | this is set to 1.0, the muscle will seek to be its initial length. | +--------------------------+--------------------------------------------------------------------------------+ | **excitation** | Controls the amount of muscle contraction. A value of "0.0" is relaxed and | | | "1.0" is fully contracted. | +--------------------------+--------------------------------------------------------------------------------+ | **endPoints** | This attribute is used to author the fiber direction field by painting 1.0 | | | in-points and 0.0 out-points that define a gradient that the fibers will flow | | | along. Regardless of what is painted, the map is rounded to 0.0, 0.5, and 1.0 | | | before use. | +--------------------------+--------------------------------------------------------------------------------+ | **weights** | A paintable attribute that is used to scale the effect of the fiber force | | | through the volume. It allows one to localize the effect of the fiber field to | | | certain parts of the tissue. As in the zMaterial node, if localized fiber | | | attenuation is required, the tet mesh will need to have enough local detail to | | | support the desired detail in the fiber field. | +--------------------------+--------------------------------------------------------------------------------+