Particle Material

Detailed information of the Omnisurface material can be found here.

Material Parameters

The particle tool comes with a default material that you can use with your particles.

This group carries your input information such as opacity and color parameters.

Inputs	Description
Opacity	Controls the overall fractional opacity of the texture.
Color	Set color R, G, B. Left Click color field for Color picker
Texture	Toggle: If enabled, allows texture loading in the Bitmap parameters -> Bitmap File field
Vertex Color	Toggle: Controls whether vertex color is enabled or disabled. Enable this if you want to change colors or over time in the particle system.
Vertex Alpha	Toggle: Controls whether vertex color alpha channel is enabled or disabled. Enable this if you want to change opacity or over time in the particle system.

You can use the color picker in the color picker parameter by clicking the color field.

This group carries your bitmap (texture) information. You can load textures and change texture and brightness here.

Bitmap Parameters	Description
Brightness	Change color brightness. This is an additive function.
Contrast	Change color contrast. This is a power function.
Invert image	Toggle: Invert Image.
Scalar mode	Dropdown: Defines how the texture applies to scalar parameters. mono_alpha mono_average mono_luminance mono_maximum
Bitmap file	Select your texture in this field using the file browse button. You can also locate files if you have a path in the field.
Bitmap File Color Space	auto raw sRGB
Color texture brightness	Change color brightness. This is an additive function.
Color texture contrast	Change color contrast. This is a power function.

This group controls the particle’s UVs.

Placement	Description
Clip	Toggle: Clamp UVs from 0 to 1. If enabled tiling past 0 to 1 does not occur.
Rotation	Rotation angle of the texture in degrees.
Tiling	Controls the scale of the texture on the object.
UV Space Index	The UV channel to pick for texture sampling.
Offset	Controls position of the texture on the object.

This group controls base diffuse texture parameters.

Base	Description
Weight	Base weight
Color	Set color R, G, B. Left Click color field for Color picker.
Diffuse Roughness	Higher roughness values lead a powdery appearance.
Metalness	Higher values lead to a more metalic appearance.

This group controls the amount of Specular to apply to the material.

Specular	Description
Weight	Specular weight
Color	Set specular color R, G, B. Left Click color field for Color picker.
Roughness	Higher roughness values lead to softer specular highlights.
IOR Preset	Dropdown: Index of refraction presets ior_custom ior_plastic ior_sapphire ior_soap_bubble ior_vacuum ior_water_0c ior_water_35c ior_water_100c
IOR	This parameter sets Index of refraction, which affects surface Fresnel reflectivity
Anisotrophy	This parameter sets the specular reflection anisotropy.
Rotation(radian)	this parameter sets the orientation of the anisotropic effect in radians.

Transmission allows light to travel through thin objects.

Transmission	Description
Enable Transmission	Enable or disable transmission in the material
Weight	Transmission weight
Color	Set transmission color R, G, B. Left Click color field for Color picker.
Depth	This parameter sets the distance traveled by refracted white rays before their colors turned into the transmission color.
Scatter	This parameter sets the scattering coefficient (sigma_s) of the interior medium to the object. The scattering color describes how much “refracted rays” are scattered while traveling inside the medium.
Scatter Anisotrophy	Values above 0.0 biases the scattering effect forward in the direction of the light, while values below 0.0 biases the scattering effect backward in the opposite direction of the light.
Dispersion ABBE	This parameter sets how much the index of refraction varies across wavelengths. Lowering the abbe number increases the effect of dispersion. When thin-walled enabled, dispersion has no effects.

Subsurface supports light entering and scattering through an object and supports non thin objects. What are the RT and PT limitations (edited)

Subsurface	Description
Enable Subsurface	Enable or disable subsurface scattering in the material
Weight	Subsurface weight
Scattering presets	Dropdown: select a subsurface scattering presets scattering_colors_custom scattering_colors_potato scattering_colors_skim_milk scattering_colors_whole_milk scattering_colors_skin_1 scattering_colors_skin_2 scattering_colors_skin_3 scattering_colors_skin_4
Color	Set subsurface color R, G, B. Left Click color field for Color picker.
Radius (mfp)	Set Radius of Subsurface Scattering.
Scale	This parameter scales the effect of scattering radius or the mean free path distance.
Anisotrophy	Values above 0.0 biases the scattering effect forward in the direction of the light, while values below 0.0 biases the scattering effect backward in the opposite direction of the light.

Note

This is not used in the particle system

Sheen simulates surface micro-fibers, with axes oriented parallel to the surface normal, creating specular highlights at grazing angles.

Sheen can create soft backscattering materials like fine powder, dust, satin, leaf, and peach fuzz on the skin

Sheen	Description
Weight	Sheen weight
Color	Set sheen color R, G, B. Left Click color field for Color picker.
Roughness	Higher roughness values lead to sharper specular highlights.

This group enables and sets an emissive color and Intensity

Emission	Description
Weight	Emission weight
Emission Mode	Dropdown: set emission mode emission_lx emission_nt
Intensity	Emission intensity multiplier
Color	Set emissive color R, G, B. Left Click color field for Color picker.
Use Temperature	toggle: When enabled, use temperature instead of assigned color
Temperature (kelvin)	Temperature value in kelvin

This layer models a reflective thin film when a metal and or specular reflection layer presents.

Thin Film	Description
Enable Thin Film	Toggle: Enable or disable thin film in the material
Thickness (mm)	Film thickness in milimeters.
IOR Preset	Dropdown: Index of refraction presets ior_custom ior_plastic ior_sapphire ior_soap_bubble ior_vacuum ior_water_0c ior_water_35c ior_water_100c
IOR	Index of refraction

This group enables and sets geometry parameters.

Geometry	Description
Thin Walled	Toggle: Enable or disable thin walled in the material
Enable Opacity	Toggle: Enable or disable opacity on geometry
Opacity	Opacity value
Opacity Threshold	Opacity threshold value.
Displacement	amount of geometry displacement in x, y, z.