Resolution and Particle Radius 

 

Overview 

Aside from collision objects, all objects in Lucid are converted to particles and internally simulated in their particle form. The size of all particles within a simulation is constant, meaning two or more separate objects will be represented as particles with the same global size. Lucid automatically generates particles for all objects based on the volume within the objects to avoid collisions between particles in the initial scene state.

The particle size plays an important role in the outcome of the simulation. Larger particles will behave differently from smaller particles. Due to the varying sizes of objects inside a simulation it is, therefore, important to understand how particle size is automatically chosen and how to be able to manually override these settings.

 

Automatic particle radius 

If the Manual Radius parameter in Flex Settings Helper is set to 0, which is the default value, Lucid will automatically determine the particle radius based on the object scale within the simulation. At the start of a simulation Lucid goes through all objects with Lucid modifier, Particle Flow Fluid Operators, and Particle Flow Geometry Operators to find the object which is the largest.

Lucid then uses this largest object scale in conjunction with Resolution parameter in Flex Settings Helper to determine the particle radius to use. The largest dimension is divided by the value of Resolution parameter to determine the radius. This radius is then used for all particles in the scene.

  • For objects with Lucid modifier the bounding box of the scene object is used to determine its size
  • For Particle Flow operators the size of the Source emitter is used to determine the scale
 

Manual particle radius 

If you want to have control over the particle scale you can change the Manual Radius parameter in Flex Settings Helper to a non-zero value. In this case the automatic particle radius process outlined above is skipped and the value you specify is used instead. Smaller particle radius values will generate more particles in the scene as Lucid attempts to fill your simulated geometry with tightly packed particles.

It is important to set the radius to the largest acceptable value for your simulation to improve performance and speed of the simulation. Lower values will make the simulation more granular at the expense of its performance.