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Introduction

 


 

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  • This lesson will take you through setting up metaballs with V-Ray
  • This information centers around the basic metaball parameters
  • The lesson topic is approximately 30 minutes in length
  • Lesson covers all 3 Learning Cycles for the Lesson Topic – Lecture, Demonstration, and Activity
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Contents


Overview
Available Materials
Lecture
Demonstration
Activity                                                                                                                                                                                                                                                     
Additional resources


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overview
overview
Overview


Goal - Develop the look for the water pouring out of a spigot. Use various meatball parameters to create different looks

Objective – We will use several parameters to convert a standard particle system into an iso-surface during rendering      

Outcome – You will understand how to work with the meatball parameters to render water in V-Ray

 

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Available materials


To set up the lesson follow the links below and download all available materials.

Lesson plan download
Presentation (Lecture) download
Demonstration tutorial download                                                          

Scenes & Assets download

 


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Lecture



1. Terminology

Here’s some terms to be aware of when thinking about metaballs.

  • Iso-surface
    • A way of displaying Computational Fluid Dynamics to help aid in studying fluid flow around objects
  • Resolution
    • The maximum detail displayed during the viewport preview
  • Threshold
    • Controls how close the iso-surface is to the particles

 

 

2. V-Ray Metaball

а) Metaball Overview

  • VRayMetaball is a geometric primitive that can be used to create a raytraced iso-surface out of an existing particle system
    • The iso-surface is ray traced at render time and no actual geometry is generated.
  • VRayMetaball node can be created from two areas
    • In the Maya menu choose Create > V-Ray > VRayMetaball
    • By clicking on the Create VRay Metaball button in the V-Ray Shelf

 

 


b) Key Parameters for metaballs
  • Particle Radius – sets the particle size if Use particle size is disabled
  • Threshold – controls how close the iso surface is to the particles
  • Smoothing field bumps – will attempt to smooth out the surface by culling away small stray particles
  • Smooth radius – the radius value when Smoothing field bumps is enabled
  • Smooth expansion – a value that further controls the smoothing
  • Show Preview – enables the viewport preview
  • Resolution – maximum grid resolution used to compute the viewport preview

 

 


c) Threshold – controls how close the iso surface is to the particles
  • Lower values move the surface away from the particles
  • Higher values make the surface cling close to the particles
  • Particle Radius – determines the size of the particles

 

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Threshold: 0.25

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Threshold: 0.5

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Radius: 1.0

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Radius: 0.85

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d) Smoothing
  • Smoothing field bumps – attempts to smooth out the surface by culling away small stray particles
  • Smooth radius – the radius of the metaballs when Smoothing field bumps is enabled
  • Smooth expansion – a value that further controls the smoothing

 

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Smooth field bumps: Off

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Smooth field bumps: On

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Sm. radius: 0.5
expansion: 0.5

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Sm. radius: 0.3
expansion: 0.245

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e) Resolution
  • The maximum grid resolution used to compute the viewport preview
  • Lower values produce a more rough approximation of the metaballs surface that takes less memory and is faster to compute
  • Higher values produce more accurate previews at the expense of more RAM and slower calculation speed

 

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Resolution: 50

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Resolution: 100

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Conclusion



 

a) Iso-surface

  • A CG version of fluid calculations

b) Smooth radius

  • Size parameter when smoothing metaballs

c) Smooth expansion                                                               

  • Fine-tunes the smoothing of the metaballs

 


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Demonstration



Time to see it work!

Watch while I demonstrate how to set up metaballs from an nParticle system

Demonstration tutorial

 

 


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Activity



Time to do it yourself!

Use the provided scene file to set up and adjust the metaballs

 

 


Dialing in the right values

  • Particle Radius: 0.755
  • Threshold: 0.450
  • Smooth field bumps: Enabled
  • Smooth radius: 0.300
  • Smooth expansion: 0.245
  • Show Preview: Enabled
  • Resolution: 100

 

 


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additionalresources
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Additional resources


Find more training resources listed below: