Limitations and Workarounds

Many simulation parameters should only be changed on the start frame.
Many parameters can only be changed on the start frame because it is technically difficult to change them on the fly (e.g. tet mesh resolution). To indicate this, these attributes are not keyable. However, changes to these attributes made on other frames should take effect once the solver is put back to the start frame. If they do not, this may indicate a bug in the software. To workaround such issues, go to the start frame, change the value to something else, and change it back again. Alternatively, run ‘ziva -refresh’ to rebuild the entire solver. If all else fails, try saving and reloading the scene. If you encounter this, please file a bug report letting us know how to reproduce the failure by emailing support@zivadynamics.com.

Quasi-static solves are not always stable.
If there are insufficient attachments to bones in the system, a quasi-static step can explode because the physical quasi-static problem is not well-posed. To solve this, add more attachments.

The quasi-static solver’s ability to reach the elastic equilibrium in one timestep can cause issues while processing collisions. If a tissue is experiencing an incorrect collision during quasi-static solving it is likely because it travelled too far in that timestep, allowing it to deeply penetrate or teleport through another tissue or bone. To reduce the distance that the tissue travels the forces on that tissue should be ramped up over multiple timesteps. This will result in more stable collisions.

Selecting Ziva nodes in the viewport doesn’t work in Viewport 2.0.
Selecting Ziva DG nodes (zAttachment, zTet, etc.) by clicking in the viewport doesn’t work with Viewport 2.0. One workaround is to switch to a legacy viewport. Another is to use the “Launch Scene Panel” capability on the Ziva menu (available since v1.4).

Ziva Logging
Ziva VFX writes a log file that can be consulted for additional information should Maya crash. The log file’s location is printed in the Maya script editor as soon as the plugin is loaded, so look there to learn where your log files are going.

On Windows, a typical log filepath is:

C:\Users\JohnSmith\AppData\Local\Temp\ziva-maya-log-1f52-836a-6dfe-8bc1.txt

On Linux, a typical log filepath is:

/usr/tmp/ziva-maya-log-660b-29e4-b27b-414d.txt

Changing mesh topology *after* applying a warping deformer (zRBFWarp, zHarmonicWarp, zBoneWarp) is not supported.

Source and target cage meshes with different mesh topology are not supported. Also, changing the source mesh, target mesh or the input mesh topology after it has been added to a warping deformer is not supported. Undefined behavior may occur if this is attempted.

For anatomy transfer, source and target cages must be in correspondence.

Ziva Anatomy Transfer tools require source and target meshes (“cages”) to be in correspondence. Undefined behavior may occur if this condition is not satisfied.

We do not provide motion retargeting tools.

We provide tools (such as zHarmonicWarp) to warp joint hierarchies from the source to the target creature. We also provide tools to transfer the Maya skin clusters. See Transferring Maya skin clusters. However, the motion of the target creature must be computed using external tools (this is called motion retargeting).