Work with particle attributes

You change the way particles look and behave by setting attributes. The type of attribute affects how you work with it.

Static attributes

Static attributes are attributes the particle object has by default. For example, a particle object’s transform node has the static attributes Translate X, Rotate Y, Scale Z, and so on. A particle object’s shape node has many static attributes that are listed in the Particle Attributes section of the Attribute Editor.

You can set the values of these attributes with the Attribute Editor, expressions, and other techniques after you create the object. The values you specify for static attributes apply to all particles in the particle object.

Dynamic attributes

Dynamic attributes have predefined names and purposes. Maya adds dynamic attributes to the particle object in response to your user interface selections. An object has no dynamic attributes unless your actions cause Maya to add them to the object.

You can set per object and per particle opacity and color of a particle object. The procedures require you to add dynamic per particle or per object attributes for the opacity and color. See Per particle and per object attributes for details on per particle and per object attributes.

You can also add default dynamic attributes for tuning particle render types (see Add dynamic attributes). For example, suppose you select a particle object and display the Render Attributes section of the Attribute Editor. If you select Spheres as the Particle Render Type then click the Add Attributes For Current Render Type button, Maya adds a Radius attribute. The Radius attribute appears at the bottom of the Render Attributes section:

By adding dynamic attributes when they’re needed, Maya runs faster. When a dynamic attribute is added to an object, the attribute appears in the Attribute Editor for the selected object.

Add dynamic attributes

You can add dynamic attributes on an individual basis. For instance, after you become familiar with the attributes of a particle render type, you can selectively add only those you need without adding all the default attributes. By adding the fewest attributes necessary, you’ll prevent unnecessary processing and avoid cluttering the Attribute Editor.

For example, suppose you select the Points render type and want to adjust only the point size of the particles. You can add only the attribute that sets the point size, while not adding any others.

To selectively add a dynamic attribute to a particle object

  1. Select the particle object.
  2. In the Add Dynamics Attributes section of the Attribute Editor, click the General button.

    The Add Attribute window is displayed.

  3. In the Add Attribute window, select the Particle tab.
  4. Select an attribute.
  5. Click Add to add an attribute.
  6. Click OK when you are done adding attributes.

Add custom attributes

Custom attributes are attributes you optionally add to an object, for example, by selecting Modify > Add Attribute. Although custom attributes are dynamically added to an object, we refer to them as custom to distinguish them from the static dynamic attributes.

Custom attributes have no direct effect on any characteristic of an object in Maya. A custom attribute is typically used in an expression to control a combination of other attributes. See Expressions for details.

Per particle and per object attributes

A per object attribute lets you set the attribute value for all particles of the object collectively with a single value. For instance, the per object opacity attribute lets you set a single opacity value for all the particles in the object.

A per particle attribute lets you set the value of the attribute individually for each particle of the object. For example, the per particle opacityPP attribute lets you set a unique opacity value for each particle. Though there is only one opacityPP attribute in a particle object, the attribute holds the value for each particle’s opacity value. The attribute holds the values in an array. In simple terms, an array is a list.

Though per particle attributes are best for creating complex effects, you can’t keyframe them. You can keyframe per object attributes.

Dynamic attributes describes how to add attributes to a particle object to enhance your control of the behavior and appearance. After you add a per object attribute to a particle shape node, the attribute appears in the particleShape tab of the Attribute Editor, for example, in the Render Attributes section. You typically set per object attribute values in the Attribute Editor or Channel Box.

After you add a per particle attribute to a particle shape node, the attribute name appears in the Per Particle (Array) Attributes section of the particleShape tab of the Attribute Editor. For details on setting values, see Set attributes on a per particle basis.

Note that a static, dynamic or custom attribute can be a per particle or per object attribute, not both. Also be aware that dynamically added per particle attributes often have a name that ends in PP. PP stands for per particle.