(GRASP) Oceanic reflection model (ocean-grasp)

Parameter	Type	Description	Flags
wavelength	float	\(k \in [200, 4000]\) nm.	Specifies the wavelength at which to evaluate the oceanic reflectance.
wind_speed	spectrum or texture	\(k \in [0, 37.54]\) m/s.	Specifies the wind speed at which to evaluate the oceanic reflectance (Default: 0.1 m/s).
eta, k	spectrum or texture	Real and imaginary components of the water’s index of refraction. (Default: 1.33, 0.)
ext_ior	spectrum or texture	Exterior index of refraction specified numerically or using a known material name. Note that the complex component is assumed to be 0 (Default: 1.000277).
water_body_reflectance	spectrum or texture	Diffuse reflectance of radiations that entered and exited the water body. (Default: 0.).
component	integer	Debug: specifies which component of the oceanic reflection model to evaluate. Default: 0 Component 0 is used to evaluate the total oceanic reflectance. Component 1 evaluates the whitecap reflectance. Component 2 evaluates the sun glint reflectance. Component 3 evaluates the underlight reflectance. Component 4 evaluates the whitecap and underlight reflectance together.
State parameters

This plugin implements the oceanic reflection model originally detailed in cite:Litvinov2024AerosolSurfaceCharacterization. Note that this model is monochromatic.

For the fundamental formulae defining the oceanic reflectance model, please refer to the Eradiate Scientific Handbook.

Note that this material is one-sided—that is, observed from the back side, it will be completely black. If this is undesirable, consider using the twosided BSDF adapter plugin. The following snippet describes an oceanic surface material with monochromatic parameters:

PYTHON

"type": "ocean_grasp",
"wavelength": 550,
"wind_speed": 10,
"eta": 1.33,
"k": 0.,
"ext_ior": 1.0,
"water_body_reflectance": 0.02,
"component": 0,

XML

<bsdf type="ocean_grasp">
    <float name="wavelength" value="550"/>
    <float name="wind_speed" value="10"/>
    <float name="eta" value="1.33"/>
    <float name="k" value="0."/>
    <float name="ext_ior" value=1.0/>
    <float name="water_body_reflectance" value=0.02/>
    <int name="component" value="0"/>
</bsdf>