Simulation States: Cache

Owned by thomas (Unlicensed)
Last updated: 14 Oct, 2016
3 min read

RealFlow's cache mode is a convenient way to reuse and protect already simulated elements:

  • When a node is in cache mode RealFlow will load its simulation data from disk and display it in the viewport.
  • Cached nodes are able to interact with other nodes, but they cannot be influenced.
  • When cached nodes are used in other simulations their data will not be overwritten.


The cache mode icon.


A typical field of application for cached nodes is the simulation of Hybrido fluids with secondary fluids, such as splashes or foam:

  • Simulate the Hybrido fluid (“core fluid”).
  • Set the domain to cache.
  • Add a splash emitter – the splashes will be created from the cached core fluid.
  • Set the splash emitter to cache.
  • Add a foam emitter – the foam particle can be created from the cached core fluid and splashes.

The advantage with this workflow is that you have full control over every simulation element. Once you are happy with the result, the node is set to cache and you can proceed with the next part. The previously simulated fluid is preserved and does not have to be re-simulated.

In order to set a node to cache, just click on the small rocket icon in the → “Nodes” panel. The yellow symbol and the yellow name indicate the cache mode:



Objects, MultiBodies and the Cache Mode

Objects can be set to cache as well, but here you have to be careful. An example: Let's say you want to set an object – Torus01 – to cache. All steps must be performed before the simulation starts:

  • Open Export > Export Central and look for the node in the “OBJECTS” branch or go to the object's "Export" tab under "Node Params".
  • Click on the “Torus01” checkbox and expand its export tree.
  • Enable “Animation (.sd)”.
  • Confirm with “Done” and simulate.

 



Now, the object's simulation data will be written to a separate file called "Torus01.sd". Only when this file exists the object's cache mode can be used. If your scene contains lots of objects simply click on the “All Objects” button in the “Export Central” (F12) window.

A situation, where cached objects are used, is a Hybrido simulation with a domain, secondary elements (splash, foam, etc.), and interacting rigid bodies. When you add the secondary elements the domain and the rigid bodies must be set to cache. Otherwise, the bodies will be re-simulated during the splash and foam passes, and will not match the core fluid anymore.