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Where does RealFlow | Cinema 4D store the cache files?

Click on the "Scene" object and open its "Cache" tab in Cinema 4D's "Attributes" manager. There, specify the "Cache Folder".

You normally do not have to worry about the cache folder's content, because all data will be managed by RealFlow | Cinema 4D during simulation.

How do I get rid of my simulation files?

Click on the "Scene" object and open its "Cache" tab in Cinema 4D's "Attributes" manager. There you will find a "Remove Cache" button.

Will the cache files be overwritten when I hit "Cache Simulation" or "Cache Meshes" again?

Yes. We therefore recommend specifying new cache folders if you want to save different versions of a simulation.

Isn't there a way to specify a default cache folder?

You can define a base path in Cinema 4D's preferences under "RealFlow". For the actual cache data we recommend specifying a separate folder for every scene, because otherwise existing data might be overwritten.

Can I use SSD drives with RealFlow | Cinema 4D?

In terms of simulation and read/write speed it definitely is a good idea to have a fast SSD drives, but these devices have a limited amount of bytes to be written –  in many cases something between 250 and 500 TB. Beyond this limit data can only be read, but no longer be written. If you consider that a large simulation can produce several gigabytes of data this lifespan is a serious thing to think about. We therefore recommend modern hard disk drives. They are slower, but much more reliable. But in the end this decision is completely up to you.

Why are the cache files so big?

RealFlow | Cinema 4D stores information for hundreds of thousands or even millions of particles – and every particle requires a certain amount data for a correct simulation. This is simply the nature of simulations, esp. with huge amounts of particles. Meshes often consist of millions of polygons with vertex data and all that has to be stored somewhere as well. And the information has to be written for every frame, otherwise it's not possible to resume simulations, or create previews and renders, for example.

RF|C4D does certainly not write Terabytes, although several Gigabytes are absolutely normal for large simulations. But mass storage became very cheap over the last years. It'd be fantastic if we're able to magic away all this information, but we're not that far...

Why does my cached simulation look completely different than my current setup?

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. The common form is name_frame.ext

  • name is the name of the stored simulation node, e.g. "Fluid" or "Rigid", but also "Cube.1", etc. in scenes with rigid/elastic deformer.
  • frame is the frame number following a 5-digit padding.
  • ext is the file extension.
What is the difference between the different Deformer Cache modes?

You can select between two (actually three if you combine them) options to cache the rigid/elastic simulations. Let us show you the advantages and disadvantages of every method:

  • Point Level Animation (PLA) Pros
    • Point Level Animation is supported by most if not all Cinema 4D compatible render engines.
    • Simulation results are kept in the very same Cinema 4D document. 
    • No extra file output is necessary.
    • Original geometry remains intact, while the duplicated geometry preserves all the characteristics of it (hierarchy, tags, materials, etc.).
  • Point Level Animation (PLA) Cons
    • A new duplicate of the geometry is generated every time the cache process is executed. Older simulations need to be removed manually if no longer necessary.
    • The original object needs to be manually disabled after the caching process to avoid misunderstandings.
    • Cinema 4D document size grows linearly with the number of simulated frames and the number of vertices of the deformed geometries.

 

  • Export File Sequence Pros
    • Document size does not grow because of the cached information.
    • Modifications are applied to the original objects. 
    • Caching process is similar to the rest of RealFlow nodes: Fluids and meshes.
  • Export File Sequence Cons
    • Motion blur does not work unless you add a Point Cache tag per object.
    • The amount of written files in the cache folder can be very large.
    • Exported files are not a standard format and cannot be reused for other purposes.
    • Nodes with the same name will generate files with the same name. This is an issue that cannot be avoided by manual renaming in some cases:
      For example: a Cloner which duplicates a geometry hierarchy with a depth of more than one level.

 

In any case, the default mode is "Point Level Animation (PLA)".

I have cached a rigid/elastic simulation, and now the cache folder contains thousands of files. Is this really necessary?

If "Export File Sequence" is selected as the Deformer Cache Mode, yes, it is necessary. Let us explain you the reasons with an example, where a sphere will be influenced through an elastic deformer:

  • The "Elastic" deformer fills the sphere with particles.
  • RealFlow | Cinema 4D simulates the behaviour of the particles in terms of motion and deformation.
  • This information will be transferred to the sphere through the "Particle Skinner" feature.
  • When you cache the simulation, the "Elastic" container files only contain the particle data, but not the deformation.
  • The deformation, on the other hand, has to be saved for each object individually in a separate file sequence.
  • Only this workflow makes sure that you will be able to playback cached simulations and render them after you have reopened a scene.

The disadvantage is a huge amount of files. With 100 elastic objects over 200 frames you will get 20,000 individual deformation files, for example.

You can select "Point Level Animation (PLA)" as Deformer Cache Mode in order to avoid writing so many files.

Which file formats are supported by RealFlow | Cinema 4D?
  • Fluid particle and mesh files are stored as a sequence of Alembic files.
  • Rigid and elastic deformer files are stored in a propietary file format. This is a temporary approach and will be changed in one of the upcoming patches.
  • Wet-dry maps are stored as a sequence of PNG files.
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