Rahman Pinty Verstraete reflection model (rpv)

Parameter	Type	Description	Flags
rho_0	spectrum or texture	\(\rho_0 \ge 0\). Default: 0.1	P ∂
k	spectrum or texture	\(k \in \mathbb{R}\). Default: 0.1	P ∂
g	spectrum or texture	\(-1 \le g \le 1\). Default: 0.0	P ∂
rho_c	spectrum or texture	Default: Equal to rho_0	P ∂

This plugin implements the reflection model proposed by [Rahman et al., 1993].

Apart from floating point values, model parameters can be defined by nested or referenced textures which are then mapped onto the shape based on its UV parameterization.

This plugin also supports the most common extension of the RPV model to four parameters, namely the \(\rho_c\) extension, as used in [Widlowski et al., 2006].

For the fundamental formulae defining the RPV 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 RPV material with monochromatic parameters:

PYTHON

"type": "rpv",
"rho_0": 0.02,
"k": 0.3,
"g": -0.12

XML

<bsdf type="rpv">
    <float name="rho_0" value="0.02"/>
    <float name="k" value="0.3"/>
    <float name="g" value="-0.12"/>
</bsdf>