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Maya Particle Systems Notes 1

Understanding and Making Particles

Prep for in-class exercise: Make a new project and call it ParticleExercise (use defaults) Drag the forks.tif image from the homework folder to the sourceimages directory in your new project.

Making particles:

Change to the Dynamics Menu Set Rules of Physics apply, calculated frame by frame not using keyframes. Particles are designed to be animated using forces like wind and gravity. There are two types - hardware and software particles

Under Particles select the Particle Tool options

Enter a Name:

Conserve means the amount of momentum of the original particle that is conserved.

1 = all momentum is conserved and fields won't effect the particles
0 = no momentum (velocity) is conserved and fields have maximum effect

3 choices - Particles via clicking, Sketching Particles, or Particle Grid

Clicking

Number of Particles - each time you click will make this many
Maximum Radius - how far apart they could randomly be placed
Hit Enter when done

Sketching

Sketch Interval - how dense the particles will be
Hit Enter when done

Grid

Particle Spacing - how far apart the particles will be in the grid
Placement:
with cursor (2D) - place two points and hit Enter for a 2D grid
with cursor (3D) - place 2 points and hit Insert and move one point down in a different view window for a 3D grid
Hit Insert again to turn off the Insert Mode and hit Enter
with textfield - enter the coordinates of the Lower Left Corner and Upper Right Corner - move mouse into window and hit ENTER

Particle Attributes (in Attribute Editor and some in Channel Box):

Particle Tab: can be keyed for whole particle not individual particles
Particle Attributes (default attributes) Transform & Shape Node (don't change Transform):
Is Dynamic ON/OFF - off will make them uneffected by forces
Dynamics Weight - effects of fields and collisions
0 = fields connected to particles have no effect
1 = default effects - can set to .5
Max Count - used with particles created by an emitter
only allows the Max # to exist - won't emit more until some die, -1 = no limit
Count - how many are there - can't edit this

Render Attributes - to set particle type and add dynamic attributes
Depth Sort - Improves render quality of transparent particles drawn from far to near - slow
Particle Render Type - particle type and how it renders

Hardware Rendered Particles with their attributes:
Will not render out when you do a Batch or Distributed Render
To get Attributes, click Add Attributes For: Current Render Type

Points - small dots
Color Accum - when overlapping particles exist it uses an additive color effect in opacity and RGB - All colors = white
Normal Dir - direction of the normal, only use if Use Lighting is turned on
1 = forward; 2 = towards the camera; 3 = backwards
Point Size = can increase or decrease size, far and near particles are the same size
Use Lighting - uses lights from the scene. If OFF particles use their own color

Multipoint - each point is multiple points, particles seem denser, used for dust, mist, clouds
Color Accum - when overlapping particles exist it uses an additive color effect in opacity and RGB - All colors = white
Multi Count - # of particles displayed per particle
Multi Radius - the sphere within which the particles for each individual particle is randomly distributed
Normal Dir - direction of the normal, only use if Use Lighting is turned on
1 = forward; 2 = towards the camera; 3 = backwards
Point Size = can increase or decrease size, far and near particles are the same size
Use Lighting - uses lights from the scene. If OFF particles use their own color
Streak - moving particles have tails, like meteors or rain. Streak length is based on velocity. If velocity is 0 you won't see a tail.
Color Accum - when overlapping particles exist it uses an additive color effect in opacity and RGB - All colors = white
Line Width - width of the streak
Normal Dir - direction of the normal, only use if Use Lighting is turned on
1 = forward; 2 = towards the camera; 3 = backwards
Tail Fade - opacity of the tail fade; 1 = opaque, 0 = transparent
Tail Size - length of the tail, faster the velocity the longer the tail. 1 = default, 0 = none, less than 1 is shorter and more than 1 is longer
Use Lighting - uses lights from the scene. If OFF particles use their own color
Multi Streak - Multipoint with a tail for each particle. Combo of Multipoint and Streak.
Color Accum - when overlapping particles exist it uses an additive color effect in opacity and RGB - All colors = white
Line Width - width of the streak
Multi Count - # of particles displayed per particle
Multi Radius - the sphere within which the particles for each individual particle is randomly distributed
Normal Dir - direction of the normal, only use if Use Lighting is turned on
1 = forward; 2 = towards the camera; 3 = backwards
Tail Fade - opacity of the tail fade; 1 = opaque, 0 = transparent
Tail Size - length of the tail, faster the velocity the longer the tail. 1 = default, 0 = none, less than 1 is shorter and more than 1 is longer
Use Lighting - uses lights from the scene. If OFF particles use their own color
Sprites - Displays a texture image at each point. Need to map an image on it. Image always faces camera, can be used for smoke, clouds, fog, and star field. If the image has an alpha channel on it then the alpha 0 will be transparent.

  • In Windows -> Rendering Editors -> Hypershade - make a Material and Color Map a FILE to it.
  • Assign the Material to the Particles (use the right mouse button on the material).
  • Turn on Shading - Smooth Shade All and Hardware Texturing

Sprite Num - if you use a series of images which one to use in the series
Sprite Scale X - .5 scales it 50% 2 scales it 200% in the X
Sprite Scale Y - scaling in the Y
Sprite Twist - - rotation of the sprite
Spheres - particles are spheres - does not work with transparency
Radius - size of sphere

Numeric - puts the particle ID # on the particle - used for debugging
Point Size - particle size
Selected Only - select Components and only those will have numbers
Software Rendered Particles with their attributes:
Have to have a light in the scene, have to apply a material to the particles.

Blobby - Called metaballs - is attracted to and melds with nearby particles
Radius - size of sphere
Threshold - how attracted it is to the nearby particles;
1 = maximum attraction; 0 = none
May need to increase Radius as you increase Threshold

Clouds - Already has the defaultParticle Shader attached, also a metaball
Better Illumination - increases self shadowing
Radius - size
Surface Shading - 0 = cloudier effect; 1 = more distinct clouds
Threshold - how much they melt together

Tube - can be tapered, must have a volumetric shader like particle cloud on it.
Radius0 - starting radius
Radius1 - end radius
Tail Size - length of tube (is multiplied by velocity) faster = longer tail

Rendering Tip: To render without particles, select particles -> Attribute Editor under Render Stats: Turn Primary Visibility OFF

Lighting Tip: Cloud, Tube, and Blobby need lights in the scene. Point, Multipoint, Streak, and Multistreak can also use the lights in a scene - all others do not.

Add Dynamic attributes: (don't add them unless needed - they use memory and compute time)

Select Per Object and it will add the new attribute to the Render Attributes

Per Object

Opacity - 0 = transparent; 1 = opaque
Color - gives you RGB values to work with - does not show up until you hit the 5 6 7 keys

Lifespan Attributes - determines when the particle dies

Number of seconds it lives after it is born. Used with emitters.
Live forever - never dies
Constant - lives for a specific time
Random - lifespan = average life, random = total distribution

Emitters - generates particles, can be moved, and keyframes set, can parent or group them to moving objects, can have stand alone emitter or an emitter can be added to an object

Creating Emitters (positional)

Particles -> Create Emitter (don't have anything selected) particle object is created and connected to the emitter

Click Play to see them in action

Creating Object Emitter - the default is omnidirectional

Select the geometry

Particles -> Emit from Object particle object is created and connected to the emitter

To emit from CVs or edit points -

Select Component - pick the points or CVs you want to emit from Particles -> Emitter from Object

If you want to Duplicate an Emitter be sure to select Upstream Graph so it gets its particles

Deleting an Emitter does not delete the particles - you must do this manually. Look in the Outliner

Create Emitter Options

Emitter Name - give it a name
Emitter Type - omni, directional, volume
Emitter Attributes (Emission Attributes in the Attribute Editor)

Rate - how many particles per second are born

Direction/Distance Attributes
Max Distance - how far away from the emitter are particles emitted
Min Distance - how close to the emitter are particles born
(it always randomly gives birth to particles between min and max)
Direction (only for directional emitters) XYZ
Spread - particles are randomly distributed in this cone area.
1 = 360° .5 = 180° .33 = 120°
For Directional Only
Basic Emission Speed Attributes:
Speed - how fast they move

Emit from Object Options

Point Emitter - emits from cvs, edit points, points on a surface or particles (select just the CVs using the select component tool)
Surface Emitter - emits from the surface of an object (object emitter)
Curve Emitter - emits from random positions on the curve

Scale Rate by Object Size - change it in relationship to the object size

Connecting 2 different particles to the same emitter:

Prep: Make an emitter

Making an empty particle object:

Connecting the particles to the emitter: