Sprite attributes

Sprite Animation

Specifies how images are assigned to the sprites. Select one of the following:

off - Each particle uses some fixed image throughout its lifetime.

on - Each particle displays a sequence of images in turn.

Sprite Start Option

Selects the technique used to assign the initial sprite to each particle. Select one of the following:

first - Every particle uses the first image in the sequence.

particleid - The particle uses its particleId value to pick an image. If the particleId is greater than the number of images in the sequence, it starts over with the first image.

random - Each particle uses a random image from the sequence.

custom - The particle uses its spriteNumPP value to select the image. You must set the spriteNumPP values by editing the particle creation expression. See To customize the selection of the initial sprite image.

ramp - Connects a ramp to the spriteNumRamp attribute of the particle object. The ramp determines the image selection. You can modify this ramp to determine which sprite receives each image.

Sprite Cycle Pattern

Specifies how the images are cycled for each particle. Select one of the following:

linearUp - Plays through the image sequence at an even speed.

easeUp - Eases in and eases out the rate that the image sequence is played. The first and last images in the sequence will be used for longer times.

linearUpDown - Plays through the image sequence at an even speed. When the end of the sequence is reached, it plays in reverse.

easeUpDown - Eases in and eases out the rate that the image sequence is played. When the end of the sequence is reached, it plays in reverse.

custom - The particle uses its spriteNumPP value to select the image. You must set the spriteNumPP values by editing the particle runtime expression. See To customize sprite cycling.

ramp - Connects a ramp to the spriteNumRamp attribute of the particle object. The ramp determines the image selection. You can modify this ramp to determine which sprite receives each image.

Sprite Cycle Length

Controls the length of each animation cycle. this is valid only if the Cycle only once during lifespan option is disabled.

Sprite Invert Cycle

Invert the meaning of the ramp’s values. Higher values use images closer to the start of the sequence.

Add Attributes For Current Render Type button

The added attribute follows:

Radius

Sets the radius of the spheres. To set the radius on a per particle basis, add the radiusPP attribute, then set its values. See Add dynamic attributes and Set attributes on a per particle basis.

Numeric

Add Attributes For Current Render Type button

The added attributes follow:

Attribute Name

Name of the attribute whose values are to be displayed. You can use static, dynamic, or per particle attributes. See Work with particle attributes for details.

Point Size

Sets the size of the particle points. Point size is unaffected by camera distance. Both far and near particles appear the same size in the workspace.

Selected Only

Displays the attribute value of currently selected particles only.

Click (the Select by Component Type icon) to select individual particles.

Blobby Surface

Add Attributes For Current Render Type button.

The added attributes follow:

Radius

Sets the radius of the Blobby Surfaces.

To set the radius on a per particle basis, add the radiusPP attribute, then set its values. See Add dynamic attributes and Set attributes on a per particle basis.

Threshold

Controls surface blending between the particles. A value of 0 creates no blending. Generally, blending increases as the value approaches 1, then decreases again above 1. The Blobby Surfaces disappear if you set the value too high.

Increasing Threshold displays the Blobby Surfaces smaller. Increase the Radius if necessary. An example of the relationship between these attribute values follows:

Cloud

Add Attributes For Current Render Type button

The added attributes follow:

Better Illumination

Provides smoother lighting and shadowing at the expense of increased processing time. See Use lights, reflections, refractions, and shadows for details on using lights and shadows.

Radius

Sets the radius of the Clouds.

To set the radius on a per particle basis, add the radiusPP attribute, then set its values. See Add dynamic attributes and Set attributes on a per particle basis.

Surface Shading

Sets how sharply the Clouds are displayed. Enter a value between 0 and 1. A value of 1 displays the Clouds more distinctly; a value of 0 creates a cloudier effect.

Threshold

Controls surface blending between the Clouds. A value of 0 creates no blending; a value of 1 creates maximum blending.

Increasing the Threshold displays the Clouds smaller, so you might need to increase the Radius as you increase Threshold.

Maya assigns the default particle cloud shader to the particle object. We recommend that you create and assign a unique particle cloud shader. Using default shading groups can cause problems if you duplicate the object. See Create raytraced shadows with particles for information on setting particle cloud shader attributes.

Tube

Add Attributes For Current Render Type button

The added attributes follow:

Radius0

Sets a radius for the tube at its starting point. See the figure that follows.

Radius1

Sets a radius for the tube at its ending point.

Tail Size

Scales the length of the tube. This value is multiplied by the particle's velocity to set the tube length. The faster the particle moves, the longer the tube.

Maya assigns the default Cloud particle material to the particle object. This material is part of the default initialParticle shading group. You can create and assign a different shading group with your own custom material.

The predefined vector array attributes are listed below:

Attribute
To add this attribute:

rgbPP
(color)

See Set particle color.

rampPosition, rampVelocity, or rampAcceleration

No action necessary. A particle object has these attributes by default.

goalOffset

See Create goals and Add dynamic attributes.

ramp for a vector array (per particle) attribute

a ramp for a float array (per particle) attribute

The predefined float array attributes are listed below:

Attribute
To add this attribute:

opacityPP
(opacity)

See Set particle opacity.

radiusPP
(radius of Blobby Surfaces, Clouds, or Spheres)

See Add dynamic attributes.

emitterNameRatePP (emission rate of a point emitter)

See Vary emission from different points of point emitters.

goalPP
(goal weight)

See Set goal weights on a per-particle basis.

goalU and goalV
(NURBS U and V position for goals)

See Add dynamic attributes.

mass

No action necessary. A particle object has this attribute by default.

spriteNumPP,
spriteScaleXPP,
spriteScaleYPP, and spriteTwistPP
(filename extension, X-axis image scale, Y-axis image scale, and image rotation angle of Sprites)

See Add dynamic attributes.

traceDepthPP
(collision detection sensitivity)

See Add dynamic attributes.

Input U or Input V menu

None

No attribute affects the ramp component. This is the default setting for Input U.

Particle’s Age

The particle object’s ageNormalized attribute. This attribute contains the particle’s age, normalized to values between 0 and 1 from birth to death. This is the default setting for Input V.

Note
Maya normalizes only the particle’s age (ageNormalized) values from 0 to 1. All other attributes control the ramp component with their literal values. If the attribute exceeds the range 0 to 1, the values in the ramp repeat. For example, a value of 1.5 represents the same position in the ramp as a value of 0.5.

attributeUPP or attributeVPP

Creates a custom attribute that controls the ramp component. The attribute is named attributeUPP or attributeVPP, where attribute is the name of the attribute that appears in the menu. You can set this attribute with an expression, ramp, or the Component Editor.

Note that you can also select attributeUPP or attributeVPP from the Attribute Editor. Simply right-click the attribute box of the per particle attribute that’s connected to a ramp, slide the pointer to the arrow to the right, and select attributeUorVPP > arrayMapper2.outValuePP.

Other attributes

The Input U and Input V menus also lists all float array attributes in the particle object. You can select one of the listed attributes to control the ramp component.

per particle attribute that’s connected to a ramp

Break Connection

Breaks the array mapper’s input to the particle shape. This menu item doesn’t delete the ramp node or array mapper. Use this menu item if you don’t want to remove the ramp when you break the connection.

Delete Array Mapper

Breaks the array mapper’s input to the particle shape by deleting the array mapper. The ramp will also be deleted if it has no other connections. Use this menu item if you no longer need the ramp in the scene.

emitted particle object

Max Count

Sets a limit on the number of particles the emitted particle object accepts from an emitter.

For example, if you set Max Count to 20, the particle object accepts new particles until it has 20 particles, then the emission turns off. If particles die and reduce the count below 20, more particles emit until the count reaches 20.

The default value of -1 means there is no limit.

Level Of Detail

Scales the number of emitted particles. You can enter a value between 0 and 1 to scale the emission rate between 0 and 100%. Scaling down the emission rate speeds scene play.

Inherit Opacity

Gives the particles the texture’s transparency using the alpha information—Alpha Gain, Alpha Offset, and Contrast (if present). If you turn on Inherit Opacity, you can use the following attributes:

Use Luminance

Uses the texture’s luminance rather than alpha information as the source of transparency.

Invert Opacity

Gives the particles a transparency opposite the texture’s transparency, whether from alpha or luminance.

 

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