Simulation Quality

Owned by thomas (Unlicensed)
Last updated: 17 Jul, 2015
3 min read

Simulation settings can be seen as RealFlow's core, because they strongly influence simulation speed and accuracy. Many problems can be solved with a few adjustments. Simulation settings can be defined

  • Globally as default values for every new scene
  • Individually for a specific scene.

 

Individual settings are saved with the scene, so you do not have to restore them. The global settings are located under

File | RealFlow > Preferences > Simulation

Individual adjustments are made in the “Simulation Options” window (see below). → Preferences and → “Simulation Options” share the same parameters, so they are explained only once.

 

RealFlow's scene-based simulation options can be found next to the "Simulate" button.

General

 

 

  • “FPS Output” determines the number of frames per second.
  • “Threads” indicates the number of processors.
  • Please bear in mind that RealFlow's multi-threading is less efficient with small amounts of particles. Sometimes you will see CPU loads of just 10%. In this case it is often better to reduce the number of threads. More information can be found → here.
  • “MIN | MAX sub steps” are responsible for the → standard particle fluid engine. In many cases it is enough to simulate with 100 or 150 sub steps.
  • If you observe instabilities or collision problems, increase “MAX sub steps”. For → elastic particles or simulations with high → particle friction or high → viscosity it can be necessary to increase both “MIN sub steps” and "MAX sub steps", or use equal values for both parameters.
  • In scenes without fluids, e.g. pure rigid/soft body simulations, → RealWave setups, or emitters with → dumb particles “MAX sub steps” can be set to 1.

Hybrido




  • The most relevant parameters are “MIN | MAX sub steps” and “MAX iterations”.
  • Settings under “Liquid – Hybrido” only affect the → HyFLIP engine. 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 → HySPH secondaries is very slow with the → liquid particle type, or if you observe stability problems.
  • The “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” does not work with every graphic board and is only relevant with → HyFLIP simulations. The typical speed boost is as if there is one additional CPU/core. If the checkbox is greyed out your graphic board is not compatible with RealFlow.

Dyverso

 

 

  • The "MIN | MAX substeps" parameters under "Stepping" are used to control Dyverso's → SPH fluid engine. The pre-adjusted values are sufficient in many cases, but for previews it is often possible to decrease "MAX substeps".
  • For the → PBD fluid type the solver's accuracy is adjusted with "MIN | MAX 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.

Caronte

 

 

  • 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.