Simulation Quality

Simulation settings can be seen as RealFlow's core, because they strongly influence simulation speed and accuracy. There are two types of settings:

  • Global "Preferences" (File | RealFlow > Preferences > Simulation) will be applied as default values to every new scene.
  • Individual "Simulation Options" (see image below) are valid for a specific scene.

Both, "Preferences" and "Simulation Options" share the same parameters, so they are explained only once. Here is where the "Simulation Options" can be found:





  • “FPS Output” determines the number of frames per second.
  • “Threads” indicates the number of processors.
  • MIN | MAX substeps” are responsible for the standard particle fluid engine. 100 or 150 "MAX substeps" or often enough.


A few tips:

  • RealFlow's multi-threading is less efficient with small amounts of particles. With low CPU loads it is often better to decrease "Threads".
  • If you observe instabilities or collision problems, increase “MAX substeps”. 
  • For simulations with high particle friction or high viscosity increase both “MIN substeps” and "MAX substeps", or use equal values for both parameters.
  • In pure rigid/soft body simulations, RealWave setups without fluids, or standard particle emitters with dumb particles, “MAX substeps” can be set to 1.


  • The most relevant parameters are “MIN | MAX sub steps” and “MAX iterations”.
  • Settings under “Liquid – Hybrido” only affect the core fluid. The default “MAX sub steps” value of 2 is sufficient in most cases. If the fluid moves very fast increase this value.
  • MIN | MAX sub steps” under “Liquid – Particles Solver” should only be changed if the simulation of "Liquid" Hybrido secondary fluids is very slow, or if you observe stability problems.
  • “MAX iterations” can be left untouched in most case. If the default values are not sufficient you will get a warning in the → “Messages” window.
  • “Use OpenCL-GPU” is only relevant with core fluid (= Hybrido domain without splashes, foam, etc.) simulations. The typical speed boost is as if there is one additional CPU/core. If the checkbox is greyed out your graphic board cannot be used.




  • The "MIN | MAX substeps" parameters under "Stepping" are used to control Dyverso's SPH fluid engine. The pre-adjusted values are often sufficient for fluids, but for granular, rigid, or elastic materials you should consider increasing the substeps.
  • For the PBD fluid type the solver's accuracy is adjusted with "MIN | MAX iterations". The pre-adjusted values are often sufficient for PBD-based fluids, but for granular, rigid, or elastic materials you should consider increasing iterations.
  • Dyverso fluids are → GPU-friendly and you can take your graphic board into account with a click on "Use OpenCL-GPU". If the checkbox is greyed out your graphic board is not compatible with RealFlow.




  • These parameters are only relevant for rigid and soft bodies.
  • “Quality” defines the simulation engine's accuracy. In many cases it is enough to work with values between 15 and 25.
  • “Low “Jittering” values help to reduce unwanted motions at the beginning and the end of a simulation.