ParticleField

ParticleField is the base schema for describing different types of concrete ParticleField implementations, such as, but not limited to, 3D Gaussian Splats.

If you need to extend UsdVol with your own particle field schemas, your custom schemas should inherit from ParticleField.

ParticleField is a concrete base schema. You can create ParticleField prims for prototyping, manually applying necessary schemas to it as needed, but in practice you’ll want to instantiate derived types, such as ParticleField3DGaussianSplat, which provide for easier validation and renderer-adoption.

All ParticleField-derived schemas are required to provide the following attributes, but are free to provide them in any form.

Position: the local space position of each particle in the field.
Kernel: the kernel that is instantiated at each particle.
Radiance: the visual appearance of the particle field.

Other optional attributes that may control the kernel instance are, but are not limited to:

Orientation: the orientation for the kernel attached to the particle, necessary if the kernel isn’t rotationally symmetric.
Scale: the size of the kernel attached to the particle, in three dimensions.
Opacity: the opacity, or weight, of the kernel attached to the particle.

UsdVol provides base applied schemas (and derived schemas) that represent these attributes. The base applied schemas, such as ParticleFieldPositionBaseAPI are provided to allow for robust validation of ParticleFields.

See Working With Particle Fields for additional best practices when working with ParticleFields.

Properties

Inherited Properties (Gprim)

doubleSided

USD type: bool

Fallback value: False

orientation

USD type: token

Fallback value: rightHanded

primvars:displayColor

USD type: color3f[]

primvars:displayOpacity

USD type: float[]

Inherited Properties (Boundable)

extent

USD type: float3[]

Inherited Properties (Xformable)

xformOpOrder

USD type: token[]

Inherited Properties (Imageable)

proxyPrim

USD type: rel (relationship)

purpose

USD type: token

Fallback value: default

visibility

USD type: token

Fallback value: inherited