Caching is an essential element with simulations in general, not only with RealFlow | Cinema 4D. As a user of MoGraph or Cinema 4D's cloth and body dynamics you are certainly aware of this process.
There are a few things you should know about caching anyway:
- RealFlow's file format for particles and meshes is Alembic Ogawa. For deformed objects a propietary format is being used, but only temporarily. We will be moving to Alembic as soon as possible.
- When a simulation is being cached the data is written to disk. Depending on the number of particles the cache files can become very large in size.
- Cached simulations cannot be influenced anymore, e.g. through daemons or objects. If you want to do that you have to re-simulate from scratch.
- It is possible to create a preview or play, stop, and resume the simulation at any frame.
- Meshing can be done in a separate pass once the particle simulation has been finished.
- Deformers caching accepts two different approaches. Saving files with the deformation information or baking Point Level Animations on a duplicate of the deformed objects.
- Rendering from cached simulations is much faster, because all the simulation and mesh data is already existing.
- As long as you don't specify another "Cache Folder" or change a fluid's/deformer's name, existing files will be overwritten when you press "Cache Simulation | Meshes" again.
For more questions and information about caching we recommend the → "Caching" page in the "Ask" section.
The Caching Process
In order to cache a particle simulation you just have to follow two simple steps (the workflow is exactly the same for meshes, but here an existing particle cache is required):
- specify the "Cache Folder" (the default folder is configured under Cinema 4D > Edit > Preferences... > RealFlow)
- open Scene > Cache and click on "Cache Simulation".
If the scene contains fluid and mesh nodes both elements will be cached together when you hit "Cache Simulation". You can avoid this if you make the "Mesher" node inactive (disable the green check mark in the "Objects" manager).
Visual Hint
When RealFlow | Cinema 4D is in cache mode ("Use Cache" is enabled) you will see a hint in the HUD and that the main logo in the viewport has changed:
The Cache Files
In Cinema 4D, scene elements can have identical names and so it is possible to have to "Fluid" containers with the exact same name:
- To avoid overlapping or overwritten data, the simulated nodes must have unique names, especially if the cache folder is being shared with other scenes. Cache file names will follow the pattern: name_frame.ext
- Objects, driven by the rigid and elastic deformer, will also have their own, individual file sequences, but in a proprietary format. We will be moving to Alembic as soon as possible.
- With rigid and elastic deformer the amount of files in your cache folder can become very large: a simulation with 100 rigid objects over 200 frames, for example, creates at least 20,000 files.
- In order to avoid writing the deformer cache files, you can bake the deformer's animation as duplicated objects with Point Level Animation. Please bear in mind that the document size will grow proportionally to the number of frames and the complexity of the deformed geometry.