Meta Shape Operator 

The Meta Shape Operator gives you the ability to create metaballs around your thinkingParticles particle systems. MetaParticles or metaballs can be used in many situations, but they are mostly used to create liquids or blobby slime effects. Metaball surfaces are procedural surfaces that are formed around the particle system and blend together to create one blobby surface that creates the look of a contiguous liquid. This surface remains closed until the particles move far enough apart to overcome the tension value and break apart into smaller blobby surfaces. Depending on the effect you want, you can get water, mercury, maple syrup and other liquid effects with varying surface tension properties.

Operator Inputs 

ON - (Bool) This input data stream determines whether the operator is considered 'on' or 'off." You can connect other operators to this input channel such as a Bool Helper to activate/deactivate the whole operator.

Time - (Time) This input data stream is used to define the local time for the operator when the user wants to override the default system time.

Particle - (Particle) This input data stream reads in the currently selected particle group that is to be given a standard shape. The data stream MUST be connected and will be highlighted yellow if it is not.

Tension - (Scalar) This input data stream is used to override the Tension spinner value within the MetaShape rollout.

Variation - (Scalar) This input data stream is used to override the Variation % spinner value within the MetaShape rollout.

Coarseness Render - (Scalar) This input data stream is used to override the Render spinner value within the MetaShape rollout.

Coarseness View - (Scalar) This input data stream is used to override the Viewport spinner value within the MetaShape rollout.

One Connected Blob - (Bool) This input data stream is used to override the One Connected checkbox state within the MetaShape rollout.

Operator Outputs 

No Operator Outputs.

Rollout Menu 

Tension - This spinner determines the "tightness" of the procedural liquid surface with regard to their tendency to blend together with neighboring particles. The higher the Tension value, the harder the blobs and the harder it is for them to merge or blend together.

Variation % - This spinner specifies the amount of variation within the Tension effect so that the surface isn't created too evenly. This can be helpful when you want a more "lumpy" effect.

Render - This spinner sets the coarseness for the metaball surface in the rendered scene. In general this specifies how accurately the metaparticle solution is calculated. The higher the Render coarseness value, the less calculation is needed and the quicker the surface is generated. However, if the coarseness is too high, there may be little or no metaparticle effect at all. Always try to set coarseness to a level just sufficient to render as smoothly as you require.

Viewport - This spinner sets the coarseness for the metaball viewport display. Usually the viewport is set to a much more coarse value than the Render coarseness to speed interaction within the 3ds Max viewports.

Relative Coarseness - determines how the coarseness values will be used. If this option is turned off, the Render Coarseness and View Coarseness values are absolute, where the height and width of each face on the blobmesh is always equal to the coarseness value. This means the faces on the blobmesh will retain a fixed size even if the metaballs change size. If this option is turned on, the size of each blobmesh face is based on the ratio of the metaball size to the coarseness, which will cause the blobmesh face size to change as the metaballs become larger or smaller.

Use Mesh - by default thinkingParticles will use spherical blobs to create a "melted" and continuos surface between multiple particles.

Large Data Optimization - This option provides an alternate method for calculating and displaying the blobmesh. This method is more efficient than the default method only when a large number of metaballs are present, such as 2000 or more. Turn on this option only when using a particle system or other object that produces a large number of metaballs.

Material - Pick this button to open a standard Material/Map browser to choose a material that will be applied to the metaball surface.