Introduction

 


 

  • 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

 


 


Contents


Overview
Available Materials
Lecture
Demonstration
Activity                                                                                                                                                                                                                                                     
Additional resources


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

 

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

 


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

 

 

Threshold: 0.25

Threshold: 0.5

 

 

Radius: 1.0

Radius: 0.85

 

 

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

 

 

Smooth field bumps: Off

Smooth field bumps: On

 

 

 

 

Sm. radius: 0.5
expansion: 0.5

Sm. radius: 0.3
expansion: 0.245

 

 

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

 

 

Resolution: 50

Resolution: 100

 


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

 


Demonstration



Time to see it work!

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

Demonstration tutorial

 

 


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

 

 


Additional resources


Find more training resources listed below: