Memory & Disk Caching
These options allow the user to choose which particles and particle attributes will be cached to both memory and disk.
Enable/Disable Memory Caching Support
Particle Groups: Use the Caching button to enable or disable disk caching.
Custom Channels: To cache custom channel use the Caching button to enable or disable caching to disk. If custom channels are not needed we advise to disable Custom Channels caching option from the Cached Attributes list.
Splines: Nodes such as Particle to Spline and Voxel to Spline have Save To Cache option that will determine whether those splines will be cached or not.
Voxel Display: Voxel grids contain vast amount of data and it would be impractical to save all this data for each frame. Thus, we have provided users with an option to cache one channel that will be used to display data. Once cached, the Channel cannot be changed without re-caching the whole sequence.
Memory Caching
When you enable memory caching, NodeWorks will efficiently store the frames of your NodeWorks simulations in memory. This means that all the intricate details of your simulation, from particles to splines and fibers, are readily available for playback. As a result, you can interact with your simulation in near-real time, and make informed creative decisions without lag or delays that are present with disk caching. Memory cache data is automatically cleared when node parameter is changed and simulation restarted.
Use the Cached Attributes rollout to select which particle attributes will be saved to both memory and disk cache.
Use Memory Cache - enable this option if you want to cache simulation to the memory.
Clear - Clears all the cached data from the memory,
Cache Size /Gb - Defines the maximum amount of memory used for caching simulation data in RAM. This is a global setting shared by all NodeWorks scenes on your computer. Once the cache size is exceeded, subsequent frames will be calculated on the fly. However, the last cached frame will still serve as the initial state for computing later frames.
NodeWorks lets you cache simulations to disk and to load them later. A cache will include particles, splines and particle shapes.
In addition to NodeWorks` native .nxd cache format, disk export also supports .prt and Alembic (.abc) file formats.
When exporting to Alembic, NodeWorks includes both particle attributes and particle shape data. The particle shape export is highly optimized, ensuring that Alembic cache files remain compact on disk - significantly smaller than equivalent exports from 3ds Max`s native Alembic tools.
This optimized approach makes Alembic an excellent choice for particle simulations export across various DCC application. However, not all applications fully support capabilities of Alembic file format. As of this writing, Houdini is the only application confirmed to import these caches correctly. For a step-by-step guide to export from NodeWorks to Houdini, please refer to the tutorial available on our YouTube channel.
Note: When importing Alembic caches, it is critical to ensure that the 3ds Max scene frame rate matches the frame rate at which the Alembic file was exported. A mismatch between these two will cause frames to be read at the wrong time, leading to offset or skipped motion, and resulting in the cache playing back incorrectly. Always verify and align the frame rates when loading Alembic files to guarantee accurate animation timing.
Use the Cached Attributes rollout to select which particle attributes will be saved to both memory and disk cache.
Path - select a path where you want to cache your simulation. For network rendering make sure that this is a network path.
The following variables can be used to define cache paths:
- 3ds Max root folder path: $maxroot
- Path to the scene file: $maxscene
- Environment path variable (retrieved from Windows Environment Variables): $env(string environment_variable_name)
Y-Up - Exports Alembic caches for applications like Maya or Houdini that have coordinate system with Y as the ???up??? axis.
Alembic Format - Choose the .abc file format:
- Ogawa - This format became available since the Alembic version 1.5, so applications there were built with older versions might not support it. It is faster and generates smaller files when compared to HDF5.
- HDF5 - That is a very common format used for various applications although Ogawa is a better choice when it comes to Alembic caches export.
Range - Defines the simulation range for export.
Start Frame - A user defined simulation export start frame.
End Frame - A user defined simulation export end frame.
Export - Click on this button to export the simulation.
Cache Loading
Custom Load Range - By default caches will be loaded for the entire NodeWorks simulation range. Enable this option to load custom frame range.
Start Frame - A user defined simulation load start frame.
End Frame - A user defined simulation load end frame.
Cache Start Frame - This parameters defines cache loading offset frame.
Before Start Frame - Choose what happens when the system tries to load cache before the Time Start.
After End Frame - Choose what happens when the system tries to load cache after the Time End.
Use Retimer - Enable this option if you want to retime caches during loading.
Time Scale Factor - Use this parameter to slow down or speed up caches playback speed..
Create Missing Channels - By enabling this option the system will create any particle custom channel that is present in the cache but not in the Workspace.
Default Particle Group - Particle will be loaded into a group it is saved to which is determined by the group name. If the group does not exist, the particle will be moved to the group as defined by this option.
Create Missing Group - By enabling this option the system will create any group that is present in the cache but not in the Workspace.
Cached Attributes
Use this rollout to choose which particle attributes are stored in memory and written to the disk cache. Attributes that are not selected will be excluded from storage, and particles will fall back to default values when scrubbing through memory-cached frames.
The rightmost column, which lists attribute names, becomes available only when the output cache format is set to Alembic. Depending on the selected preset - Houdini or Bifrost - the attribute names are automatically adjusted to match the target application, minimizing the need for manual changes during import.
Because this dialog controls both disk and memory caching, attributes marked with an asterisk (*) are not written to the disk cache but can still be enabled or disabled for memory caching.
PRT Cache Mode - This option applies only to disk caching when the export format is set to `.prt`. It lets you choose which particle type to export: standard particles, PBD liquid particles, or PBD liquid foam.