"""Radiance Trans Material.
http://radsite.lbl.gov/radiance/refer/ray.html#Trans
https://radiance-online.org//community/workshops/2010-freiburg/PDF/DavidMead.pdf
"""
from .materialbase import RadianceMaterial
from ..datatype import RadianceNumber
[docs]class Trans(RadianceMaterial):
"""Radiance translucent material."""
r_reflectance = RadianceNumber('r_reflectance', num_type=float, valid_range=(0, 1))
g_reflectance = RadianceNumber('g_reflectance', num_type=float, valid_range=(0, 1))
b_reflectance = RadianceNumber('b_reflectance', num_type=float, valid_range=(0, 1))
specularity = RadianceNumber('specularity', num_type=float, valid_range=(0, 1))
roughness = RadianceNumber('roughness', num_type=float, valid_range=(0, 1))
transmitted_diff = \
RadianceNumber('transmitted_diff', num_type=float, valid_range=(0, 1))
transmitted_spec = \
RadianceNumber('transmitted_spec', num_type=float, valid_range=(0, 1))
def __init__(self, name, r_reflectance=0.0, g_reflectance=0.0, b_reflectance=0.0,
specularity=0.0, roughness=0.0, transmitted_diff=0.0,
transmitted_spec=0.0, modifier="void"):
"""Create trans material.
Attributes:
name: Material name as a string. Do not use white space and special
character.
r_reflectance: Reflectance for red. The value should be between 0 and 1
(Default: 0).
g_reflectance: Reflectance for green. The value should be between 0 and 1
(Default: 0).
b_reflectance: Reflectance for blue. The value should be between 0 and 1
(Default: 0).
specularity: Fraction of specularity. Specularity fractions greater than 0.1
are not realistic (Default: 0).
roughness: Roughness is specified as the rms slope of surface facets. A
value of 0 corresponds to a perfectly smooth surface, and a value of 1
would be a very rough surface. Roughness values greater than 0.2 are not
very realistic. (Default: 0).
transmitted_diff: The transmitted diffuse component is the fraction of
transmitted light that is transmitted diffusely in as scattering fashion.
transmitted_spec: The transmitted specular component is the fraction of
transmitted light that is not diffusely scattered.
modifier: Material modifier (Default: "void").
"""
RadianceMaterial.__init__(self, name, modifier=modifier)
self.r_reflectance = r_reflectance
"""Reflectance for red. The value should be between 0 and 1 (Default: 0)."""
self.g_reflectance = g_reflectance
"""Reflectance for green. The value should be between 0 and 1 (Default: 0)."""
self.b_reflectance = b_reflectance
"""Reflectance for blue. The value should be between 0 and 1 (Default: 0)."""
self.specularity = specularity
"""Fraction of specularity. Specularity fractions greater than 0.1 are not
realistic (Default: 0)."""
self.roughness = roughness
"""Roughness is specified as the rms slope of surface facets. A value of 0
corresponds to a perfectly smooth surface, and a value of 1 would be a
very rough surface. Roughness values greater than 0.2 are not very realistic.
(Default: 0)."""
self.transmitted_diff = transmitted_diff
self.transmitted_spec = transmitted_spec
self._update_values()
[docs] @classmethod
def from_reflected_spacularity(
cls, name, r_reflectance=0.0, g_reflectance=0.0, b_reflectance=0.0,
reflected_spacularity=0.0, roughness=0.0, transmitted_diff=0.0,
transmitted_spec=0.0, modifier="void"):
"""Create trans material from reflected spacularityself.
See:
https://radiance-online.org//community/workshops/2010-freiburg/PDF/DavidMead.pdf
Attributes:
name: Material name as a string. Do not use white space and special
character.
r_reflectance: Reflectance for red. The value should be between 0 and 1
(Default: 0).
g_reflectance: Reflectance for green. The value should be between 0 and 1
(Default: 0).
b_reflectance: Reflectance for blue. The value should be between 0 and 1
(Default: 0).
reflected_spacularity: Fraction of reflected spacular. The reflected
specularity of common uncoated glass is around .06, Matte = min 0,
Satin = suggested max 0.07 (Default: 0).
roughness: Roughness is specified as the rms slope of surface facets. A
value of 0 corresponds to a perfectly smooth surface, and a value of 1
would be a very rough surface. Roughness values greater than 0.2 are not
very realistic. (Default: 0).
transmitted_diff: The transmitted diffuse component is the fraction of
transmitted light that is transmitted diffusely in as scattering fashion.
transmitted_spec: The transmitted specular component is the fraction of
transmitted light that is not diffusely scattered.
modifier: Material modifier (Default: "void").
"""
cr, cg, cb, rs, roughness, td, ts = \
r_reflectance, g_reflectance, b_reflectance, reflected_spacularity, \
roughness, transmitted_diff, transmitted_spec
rd = (0.265 * cr + 0.670 * cg + 0.065 * cb)
absorb = 1 - td - ts - rd - rs
if absorb < 0:
summ = td + ts + rd + rs
msg = 'Sum of Diffuse Transmission (%.3f), Specular Transmission (%.3f),' \
'Specular Reflection (%.3f) and Diffuse Reflection (%.3f) cannot be ' \
'more than 1 (%.3f).' % (td, ts, rs, rd, summ)
raise ValueError(msg)
# calculate the material
a7 = ts / (td + ts)
a6 = (td + ts) / (rd + td + ts)
a5 = roughness
a4 = rs
a3 = cb / ((1 - rs) * (1 - a6))
a2 = cg / ((1 - rs) * (1 - a6))
a1 = cr / ((1 - rs) * (1 - a6))
if a3 > 1 or a2 > 1 or a1 > 1:
raise ValueError(
'This material is physically impossible to create!\n'
'You need to adjust the inputs for diffuse reflectance values.')
return(cls, name, a1, a2, a3, a4, a5, a6, a7, modifier)
[docs] @classmethod
def from_string(cls, material_string, modifier=None):
"""Create a Radiance material from a string.
If the material has a modifier the modifier material should also be partof the
string or should be provided using modifier argument.
"""
modifier, name, base_material_data = cls._analyze_string_input(
cls.__name__.lower(), material_string, modifier)
_, _, _, r_reflectance, g_reflectance, b_reflectance, specularity, \
roughness, transmitted_diff, transmitted_spec = base_material_data
return cls(name, r_reflectance, g_reflectance, b_reflectance, specularity,
roughness, transmitted_diff, transmitted_spec, modifier)
[docs] @classmethod
def from_json(cls, rec_json):
"""Make radiance material from json
{
"modifier": {} or void, // Material modifier
"type": "trans", // Material type
"name": "", // Material Name
"r_reflectance": float, // Reflectance for red
"g_reflectance": float, // Reflectance for green
"b_reflectance": float, // Reflectance for blue
"specularity": float, // Material specularity
"roughness": float, // Material roughness
"transmitted_diff": float,
"transmitted_spec": float
}
"""
modifier = cls._analyze_json_input(cls.__name__.lower(), rec_json)
return cls(name=rec_json["name"],
r_reflectance=rec_json["r_reflectance"],
g_reflectance=rec_json["g_reflectance"],
b_reflectance=rec_json["b_reflectance"],
specularity=rec_json["specularity"],
roughness=rec_json["roughness"],
transmitted_diff=rec_json["transmitted_diff"],
transmitted_spec=rec_json["transmitted_spec"],
modifier=modifier)
[docs] @classmethod
def by_single_reflect_value(cls, name, rgb_reflectance=0.0, specularity=0.0,
roughness=0.0, transmitted_diff=0.0,
transmitted_spec=0.0, modifier="void"):
"""Create trans material with single reflectance value.
Attributes:
name: Material name as a string. Do not use white space and special character
rgb_reflectance: Reflectance for red, green and blue. The value should be
between 0 and 1 (Default: 0).
specularity: Fraction of specularity. Specularity fractions greater than 0.1
are not realistic (Default: 0).
roughness: Roughness is specified as the rms slope of surface facets. A value
of 0 corresponds to a perfectly smooth surface, and a value of 1 would be
a very rough surface. Roughness values greater than 0.2 are not very
realistic. (Default: 0).
transmitted_diff: The transmitted diffuse component is the fraction of
transmitted light that is transmitted diffusely in as scattering fashion.
transmitted_spec: The transmitted specular component is the fraction of
transmitted light that is not diffusely scattered.
modifier: Material modifier (Default: "void").
Usage:
wallMaterial = trans.by_single_reflect_value("generic wall", .55)
print(wallMaterial)
"""
return cls(name, r_reflectance=rgb_reflectance, g_reflectance=rgb_reflectance,
b_reflectance=rgb_reflectance, specularity=specularity,
roughness=roughness, transmitted_diff=transmitted_diff,
transmitted_spec=transmitted_spec, modifier=modifier)
@property
def average_reflectance(self):
"""Calculate average reflectance of trans material."""
return (0.265 * self.r_reflectance + 0.670 * self.g_reflectance +
0.065 * self.b_reflectance) * (1 - self.specularity) + self.specularity
@property
def specular_sampling_threshold(self):
"""Specular sampling threshold (-st)."""
return self.transmitted_diff * self.transmitted_spec * \
(1 - (0.265 * self.r_reflectance + 0.670 * self.g_reflectance +
0.065 * self.b_reflectance)) * self.specularity
def _update_values(self):
"update value dictionaries."
self._values[2] = [
self.r_reflectance, self.g_reflectance, self.b_reflectance,
self.specularity, self.roughness, self.transmitted_diff,
self.transmitted_spec
]
[docs] def to_json(self):
"""Translate radiance material to json
{
"type": "trans", // Material type
"name": "", // Material Name
"r_reflectance": float, // Reflectance for red
"g_reflectance": float, // Reflectance for green
"b_reflectance": float, // Reflectance for blue
"specularity": float, // Material specularity
"roughness": float, // Material roughness
"transmitted_diff": float,
"transmitted_spec": float
}
"""
return {
"modifier": self.modifier.to_json(),
"type": "trans",
"name": self.name,
"r_reflectance": self.r_reflectance,
"g_reflectance": self.g_reflectance,
"b_reflectance": self.b_reflectance,
"specularity": self.specularity,
"roughness": self.roughness,
"transmitted_diff": self.transmitted_diff,
"transmitted_spec": self.transmitted_spec
}
