Creating Liquid Effects Using nParticles
Maya’s nParticles software allows users to give their objects properties that appear as if they are flowing like liquids. This includes giving the effect of running water, flowing lava and the like. As long as someone has some skills with this software, it should be fairly easy to learn.
Step 1: Liquid Simulation
Within the nParticles software, there is a tool known as Liquid Simulation. This tool allows the users to create liquid simulations, including drops of water, flowing mud and water splashes.
When attempting to create this effect, first select the Water nParticle effect when starting to create the object. This will add some built-in presets to the object that can be used to later create the liquid simulations.
Step 2: Select the Right nParticle Attribute
nParticle has a number of attributes that can be directly used to create flowing water. Once these attributes are added, the object should resemble flowing water.
Most of these attributes can be used for contained liquids or small flows. If a user wishes to create larger water effects, including lakes, swimming pools or rivers, then it will probably be best to use the Maya Pond or Ocean effects.
Step 3: Collide
First, turn off the Self Collide attribute. Then, adjust the Collide Width Scale if the liquid is contained within something like a glass.
Step 4: Start the Simulation
Select the Enable Liquid Simulation, which allows nParticle to overlap objects like lava over a mountain. Manipulate the Radius to determine how large the flow should be. The Radius needs to be manipulated to give the flowing water a smooth look, but avoid over-manipulating the Radius. If this happens, the nParticle collisions will increase, giving it an unnatural look.
Step 5: Increase Liquid Radius Scale
The Liquid Radius Scale indicates how much objects should overlap. Liquids contained within something should overlap at values less than 1.0. But, do not set the values less than 0.1, or the objects will not overlap enough.
Step 6: Incompressibility and Viscosity
Incompressibility determines how much the simulation should withstand compression. These values can be set as high as 10 without causing the simulation to become unstable.
The Viscosity setting determines how thick the liquid should be. For example, water will not be very thick, but lava would be. Use the Viscosity Scale ramp to add different effects, such as Age, which will cause the liquid to become thicker over time.
Step 7: Surface Tension and Threshold
Surface Tension will help keep individual objects together, which is important when the liquid starts moving or if it is suspended. This should be done on a per-particle basis, and this can be done using the Surface Tension Scale.
The Threshold allows the user to manipulate the surface of the particles. For example, they can either make them smooth or bumpy depending on the type of simulation. This tool can also be used to increase or decrease the surface size of the particles.
Step 8: Change the Simulation into a Polygon Mesh
Once done with the simulation, it can be converted into a polygon mesh. To do this, go into Modify -> Convert, and then select nParticle to Polygons.