There are four file formats from which you can choose to create point cache files: ICECache, PointCache2 (PC2), nCache, or Custom.

You can set the default file format to use in the Simulation Preferences property editor.

• The ICECache (.icecache) file format is used for caching an object's local or global point positions at each frame, including when the number of points changes, such as with particle simulations. It also caches ICE attributes.

  There is file format documentation for the ICE cache file format on the Softimage wiki — ICE Cache File Format. This allows you to write something that will get you the information you want. There is also an example in the Softimage SDK which is able to extract the information from an ICE cache file sequence.

  You can also set the XSI_CACHE_ASCII environment variable to save the .icecache file sequence in ASCII. This helps you visualize the format so that you can write your own plug-in.

• The nCache file format (.xml) lets you to create special Autodesk cache files that store the simulated point data for a point cloud driven by an ICE tree. In Autodesk Maya, you can apply the nCache file to an nParticle object. ICE attributes are cached for the point cloud and then translated to corresponding attributes in Maya. See Interoperability with Other Autodesk Products and Supported nCache Attributes for more information.

  You can also store the animated deformations from a Face Robot head using the nCache file format, then apply that nCache to the Face Robot mesh that has been exported to Maya.

  NoteYou cannot save a cache file in the nCache file format from the Cache on File node in the ICE tree. As well, a cache file created with the nCache format cannot be used in the animation mixer.

• The PointCache2 (.pc2) file format is used for caching only an object's global point positions (it does not cache any other attributes) at each frame when the number of points never changes, such as for animated or simulated deformations.

  This format is supported by most other 3D packages, such as Maya or 3DS Max, either natively or through plug-ins.

• The Custom file format is one for which you have created your own custom plug-in for caching. You must enter the file extension for the custom file format.

  You can currently only save out information (such as for bringing to another 3D package) because the Softimage SDK currently only supports Read methods.