Arnold User Data Support

 

 

 

FumeFX is tightly integrated with the Arnold renderer and allows user to export particle attributes to Arnold user data that can be used within the shader network. Custom Channels are available for particle shapes, shape instances and points.

 

Attribute - Specify the particle attribute you want to export as Arnold user data.

 

User Data - Attribute name that is accessible inside the Arnold`s shader network (fxp_age for example).

 

Normalize - Some attributes include a Normalize option that remaps their values into the [0-1] range. For example, when using normalized Age, the particle???s age is expressed as a value between 0 and 1 based on its lifetime, where 0 represents birth and 1 represents the end of life. This is especially useful when driving parameters such as an Arnold Color Ramp or other gradient-based controls.

For other attributes, normalization is performed by remapping values between the minimum and maximum values of all particles in the current frame.

 

ID - Particle ID.

• Arnold User Data: fxp_id, fxp_id_min, fxp_id_max.
• Data type: integer.

 

Age - Particle Age.

• Arnold User Data: fxp_age, fxp_age_min, fxp_age_max.
• Data type: float.

 

Life - Particle Life.

• Arnold User Data: fxp_life, fxp_life_min, fxp_life_max.
• Data type: float.

 

Radius - Particle Radius (X component of particle Scale).

• Arnold User Data: fxp_id, fxp_id_min, fxp_id_max.
• Data type: float.

 

Mass - Particle Mass.

• Arnold User Data: fxp_mass, fxp_mass_min, fxp_mass_max.
• Data type: float.

 

Speed - Particle Speed (length of Velocity vector).

• Arnold User Data: fxp_speed, fxp_speed_min, fxp_speed_max.
• Data type: float.

 

Velocity - Particle Velocity.

• Arnold User Data: fxp_velocity, fxp_velocity_min, fxp_velocity_max.
• Data type: vector.

 

Color - Particle Color.

• Arnold User Data: fxp_color, fxp_color_min, fxp_color_max.
• Data type: rgb.

 

Travel Distance - Particle Travel Distance.

• Arnold User Data: fxp_traveldist, fxp_traveldist_min, fxp_traveldist_max.
• Data type: float.

 

Custom Channels - Enable this checkbox to export custom channels. Custom channels will be listed as soon as they are added to the Workspace. However, only those channels that have specified User Data name will be exported. Supported channel types are bool, integer, float and vector.

 

Note: User Data names for Custom Channels must not contain blank spaces.

 

In the following example, the particle system`s age attribute is exported as `fxp_age`. With the Age Normalize option enabled, `fxp_age` values are normalized to a range between 0 and 1. This normalized value is accessed from the User Data Float and is used to interpolate colors within the Ramp RGB node. The resulting color is then applied as the Base Color of the Arnold Standard Surface material. Particles are rendered as Arnold points.