Ziva VFX has several ways to preserve volume, described in the Volume Preservation section. Setting zMaterial.volumeConservation to anything other than zero causes simulations to slow down. For faster runtimes, prefer to use zTissue.compressionResistance when possible.
Inertial Damping and Volume Conservation Together
If Inertial Damping and Volume Conservation are both disabled (zTissue.inertialDamping=0 and zMaterial.volumeConservation=0), then the solver may use a faster algorithm. If either term is enabled anywhere in the scene, a slower algorithm is used.
This applies to attachment stiffness, contact stiffness, Young’s modulus, tensile stiffness, shear stiffness, and bend stiffness.
When possible, do not set stiffness to very large numbers. The visible difference between an attachment stiffness of 10^8 and 10^12 may be minimal, but that higher stiffness can cause the simulation to be ill-conditioned and take longer to solve. Whether or not this will affect the runtime speed is impossible to predict. It is not guaranteed to have any affect at all and smoothly changing stiffnesses will not smoothly change runtime speed.