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Create Liquid Simulations with nParticles
 
 
 

Liquid Simulation attributes set the appearance and control the behavior of liquid nParticles. When Liquid Simulation is enabled, individual nParticles can overlap, forming the continuous surface of the nParticle liquid. The amount of overlap is determined by Liquid Radius Scale. When Liquid Radius Scale is set to 1.0 (default value), nParticles whose outside radii (or areas of 0 density) touch will overlap to form groups of particles that render as a smooth liquid surface.

Other nParticle attributes, including Radius, Collide Width Scale, and Threshold affect the look and behavior of your liquid simulation in the following ways:

nParticle attribute Effect on Liquid Simulations
Radius Determines the overall surface of the nParticle liquid. Increasing Radius can increase the tendency of particle overlap, and therefore improves the smoothness of the liquid's surface. nParticle overlap is also determined by Liquid Radius Scale. Adjusting Radius can also affect nParticle collisions. Increasing Radius may result in interpenetrations with other Nucleus objects.
Collide Width Scale When liquid nParticles are contained in geometry, such as a passive collision glass, you may need to adjust the nParticle Collide Width Scale to avoid interpenetrations. Setting Collide Width Scale to a value that is one third the value of the object's Radius works well for most liquid simulations. See Collide Width Scale.
Threshold Threshold determines the size and smoothness of the nParticle’s rendered surface by controlling the density of the overlapping particles. Threshold affects how your liquid nParticles look when rendered, but it does not affect how the nParticles behave in the simulation. See Set Threshold.

When creating nParticle liquid simulations, ensure that the nParticle object's Self Collide attribute is turned off. Otherwise, your nParticles will not overlap, and therefore will not produce a smooth rendered surface.

To set Liquid Simulation attributes

  1. In the scene view, select your Water style nParticle object.

    If you have not created a Water style nParticle object do so now. See Create nParticles.

    NoteYou can also enable Liquid Simulation for Ball style nParticle objects, however these nParticle objects may not look or behave like liquids when rendered.
  2. In the Attribute Editor, select the object’s nParticleShape tab.
  3. In the Liquid Simulation section, ensure that Enable Liquid Simulation is turned on.

    By default, Enable Liquid Simulation is turned on when Water style nParticle objects are created.

  4. Set Incompressibility to specify the amount you want the liquid to resist compression.

    The following images show unrendered nParticles set to different Incompressibility values. See Incompressibility.

  5. Set Viscosity to control the liquid’s resistance to flow. This sets or how thick and non-liquid the material is. See Viscosity.
  6. Set Rest Density to specify the arrangement of nParticles in the liquid when the nParticle object is at rest. See Rest Density.
  7. Set Liquid Radius Scale to specify the amount of overlap between individual nParticles.

    nParticle overlap is also affected by nParticle Radius. The following images show unrendered and rendered nParticles with Liquid Radius Scale set to different values. In each example Radius is set to 0.06. See Liquid Radius Scale.

After achieving the liquid appearance and behavior you want, you can convert the liquid nParticle object to a polygon geometry.

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