Built in Entities

For convenience, appleseed includes a number of built-in entity models, providing a robust foundation with no external dependencies. This document describes these built-in entity models in details.

This document was generated automatically using the dumpmetadata tool that ships with appleseed.

1. Built-in AOV Models

1.1. The depth_aov Model

1.2. The diffuse_aov Model

1.3. The direct_diffuse_aov Model

1.4. The direct_glossy_aov Model

1.5. The emission_aov Model

1.6. The glossy_aov Model

1.7. The indirect_diffuse_aov Model

1.8. The indirect_glossy_aov Model

1.9. The normal_aov Model

1.10. The uv_aov Model

2. Built-in BSDF Models

2.1. The ashikhmin_brdf Model

Parameter	Label	Presence	Default	Description
diffuse_reflectance	Diffuse Reflectance	required	0.5
diffuse_reflectance_multiplier	Diffuse Reflectance Multiplier	optional	1.0
glossy_reflectance	Glossy Reflectance	required	0.5
glossy_reflectance_multiplier	Glossy Reflectance Multiplier	optional	1.0
fresnel_multiplier	Fresnel Multiplier	optional	1.0
shininess_u	Shininess U	required	100.0
shininess_v	Shininess V	required	100.0

2.2. The blinn_brdf Model

Parameter	Label	Presence	Default	Description
exponent	Exponent	required	0.5
ior	Index of Refraction	required	1.5

2.3. The bsdf_blend Model

Parameter	Label	Presence	Default	Description
bsdf0	BSDF 1	required	None
bsdf1	BSDF 2	required	None
weight	Weight	required	0.5

2.4. The bsdf_mix Model

Parameter	Label	Presence	Default	Description
bsdf0	BSDF 1	required	None
weight0	Weight 1	required	0.5
bsdf1	BSDF 2	required	None
weight1	Weight 2	required	0.5

2.5. The diffuse_btdf Model

Parameter	Label	Presence	Default	Description
transmittance	Transmittance	required	0.5
transmittance_multiplier	Transmittance Multiplier	optional	1.0

2.6. The disney_brdf Model

Parameter	Label	Presence	Default	Description
base_color	Base Color	required	0.9
subsurface	Subsurface	optional	0.0
metallic	Metallic	optional	0.0
specular	Specular	optional	0.0
specular_tint	Specular Tint	optional	0.0
anisotropic	Anisotropic	optional	0.0
roughness	Roughness	optional	0.1
sheen	Sheen	optional	0.0
sheen_tint	Sheen Tint	optional	0.0
clearcoat	Clearcoat	optional	0.0
clearcoat_gloss	Clearcoat Gloss	optional	1.0

2.7. The glass_bsdf Model

Parameter	Label	Presence	Default	Description
mdf	Microfacet Distribution Function	required	ggx	Possible values are: beckmann (Beckmann), ggx (GGX), std (STD).
surface_transmittance	Surface Transmittance	required	0.85
surface_transmittance_multiplier	Surface Transmittance Multiplier	optional	1.0
reflection_tint	Reflection Tint	optional	1.0
refraction_tint	Refraction Tint	optional	1.0
ior	Index of Refraction	required	1.5
roughness	Roughness	optional	0.15
highlight_falloff	Highlight Falloff	optional	0.4
anisotropy	Anisotropy	optional	0.0
volume_parameterization	Volume Absorption Parameterization	required	transmittance	Possible values are: absorption (Absorption), transmittance (Transmittance).
volume_transmittance	Volume Transmittance	optional	1.0
volume_transmittance_distance	Volume Transmittance Distance	optional	0.0
volume_absorption	Volume Absorption	optional	0.0
volume_density	Volume Density	optional	0.0
volume_scale	Volume Scale	optional	1.0

2.8. The glossy_brdf Model

Parameter	Label	Presence	Default	Description
mdf	Microfacet Distribution Function	required	ggx	Possible values are: beckmann (Beckmann), ggx (GGX), std (STD).
reflectance	Reflectance	required	0.75
reflectance_multiplier	Reflectance Multiplier	optional	1.0
roughness	Roughness	optional	0.15
highlight_falloff	Highlight Falloff	optional	0.4
anisotropy	Anisotropy	optional	0.0
ior	Index of Refraction	required	1.5

2.9. The kelemen_brdf Model

Parameter	Label	Presence	Default	Description
matte_reflectance	Matte Reflectance	required	0.5
matte_reflectance_multiplier	Matte Reflectance Multiplier	optional	1.0
specular_reflectance	Specular Reflectance	required	0.5
specular_reflectance_multiplier	Specular Reflectance Multiplier	optional	1.0
roughness	Roughness	required	0.5

2.10. The lambertian_brdf Model

Parameter	Label	Presence	Default	Description
reflectance	Reflectance	required	0.5
reflectance_multiplier	Reflectance Multiplier	optional	1.0

2.11. The metal_brdf Model

Parameter	Label	Presence	Default	Description
mdf	Microfacet Distribution Function	required	ggx	Possible values are: beckmann (Beckmann), ggx (GGX), std (STD).
normal_reflectance	Normal Reflectance	required	0.92
edge_tint	Edge Tint	required	0.98
reflectance_multiplier	Reflectance Multiplier	optional	1.0
roughness	Roughness	optional	0.15
highlight_falloff	Highlight Falloff	optional	0.4
anisotropy	Anisotropy	optional	0.0

2.12. The orennayar_brdf Model

Parameter	Label	Presence	Default	Description
reflectance	Reflectance	required	0.5
reflectance_multiplier	Reflectance Multiplier	optional	1.0
roughness	Roughness	required	0.1

2.13. The plastic_brdf Model

Parameter	Label	Presence	Default	Description
mdf	Microfacet Distribution Function	required	ggx	Possible values are: beckmann (Beckmann), ggx (GGX), gtr1 (GTR1), std (STD).
specular_reflectance	Specular Reflectance	required	1.0
specular_reflectance_multiplier	Specular Reflectance Multiplier	optional	1.0
roughness	Roughness	optional	0.15
highlight_falloff	Highlight Falloff	optional	0.4
ior	Index of Refraction	required	1.5
diffuse_reflectance	Diffuse Reflectance	required	0.5
diffuse_reflectance_multiplier	Diffuse Reflectance Multiplier	optional	1.0
internal_scattering	Internal Scattering	optional	1.0

2.14. The sheen_brdf Model

Parameter	Label	Presence	Default	Description
reflectance	Reflectance	required	0.5
reflectance_multiplier	Reflectance Multiplier	optional	1.0

2.15. The specular_brdf Model

Parameter	Label	Presence	Default	Description
reflectance	Reflectance	required	0.5
reflectance_multiplier	Reflectance Multiplier	optional	1.0

2.16. The specular_btdf Model

Parameter	Label	Presence	Default	Description
reflectance	Reflectance	required	0.5
reflectance_multiplier	Reflectance Multiplier	optional	1.0
transmittance	Transmittance	required	0.5
transmittance_multiplier	Transmittance Multiplier	optional	1.0
fresnel_multiplier	Fresnel Multiplier	optional	1.0
ior	Index of Refraction	required	1.5
volume_density	Volume Density	optional	0.0
volume_scale	Volume Scale	optional	1.0

3. Built-in BSSRDF Models

3.1. The better_dipole_bssrdf Model

Parameter	Label	Presence	Default	Description
weight	Weight	optional	1.0
reflectance	Diffuse Surface Reflectance	required	0.5
reflectance_multiplier	Diffuse Surface Reflectance Multiplier	optional	1.0
mfp	Mean Free Path	required	0.5
mfp_multiplier	Mean Free Path Multiplier	optional	1.0
ior	Index of Refraction	required	1.3
fresnel_weight	Fresnel Weight	optional	1.0

3.2. The directional_dipole_bssrdf Model

Parameter	Label	Presence	Default	Description
weight	Weight	optional	1.0
reflectance	Diffuse Surface Reflectance	required	0.5
reflectance_multiplier	Diffuse Surface Reflectance Multiplier	optional	1.0
mfp	Mean Free Path	required	0.5
mfp_multiplier	Mean Free Path Multiplier	optional	1.0
ior	Index of Refraction	required	1.3
fresnel_weight	Fresnel Weight	optional	1.0

3.3. The gaussian_bssrdf Model

Parameter	Label	Presence	Default	Description
weight	Weight	optional	1.0
reflectance	Reflectance	required	0.5
reflectance_multiplier	Reflectance Multiplier	optional	1.0
mfp	Mean Free Path	required	0.5
mfp_multiplier	Mean Free Path Multiplier	optional	1.0
ior	Index of Refraction	required	1.3
fresnel_weight	Fresnel Weight	optional	1.0

3.4. The normalized_diffusion_bssrdf Model

Parameter	Label	Presence	Default	Description
weight	Weight	optional	1.0
reflectance	Diffuse Surface Reflectance	required	0.5
reflectance_multiplier	Diffuse Surface Reflectance Multiplier	optional	1.0
mfp	Mean Free Path	required	0.5
mfp_multiplier	Mean Free Path Multiplier	optional	1.0
ior	Index of Refraction	required	1.3
fresnel_weight	Fresnel Weight	optional	1.0

3.5. The standard_dipole_bssrdf Model

Parameter	Label	Presence	Default	Description
weight	Weight	optional	1.0
reflectance	Diffuse Surface Reflectance	required	0.5
reflectance_multiplier	Diffuse Surface Reflectance Multiplier	optional	1.0
mfp	Mean Free Path	required	0.5
mfp_multiplier	Mean Free Path Multiplier	optional	1.0
ior	Index of Refraction	required	1.3
fresnel_weight	Fresnel Weight	optional	1.0

4. Built-in Camera Models

4.1. The orthographic_camera Model

Parameter	Label	Presence	Default	Description
shutter_open_time	Shutter Open Time	optional	0.0
shutter_close_time	Shutter Close Time	optional	1.0
film_dimensions	Film Dimensions	required	None
film_width	Film Width	required	None
film_height	Film Height	required	None
aspect_ratio	Aspect Ratio	required	None
near_z	Near Z	optional	-0.001

4.2. The pinhole_camera Model

Parameter	Label	Presence	Default	Description
shutter_open_time	Shutter Open Time	optional	0.0
shutter_close_time	Shutter Close Time	optional	1.0
film_dimensions	Film Dimensions	required	None
film_width	Film Width	required	None
film_height	Film Height	required	None
aspect_ratio	Aspect Ratio	required	None
focal_length	Focal Length	required	None
horizontal_fov	Horizontal FOV	required	None
near_z	Near Z	optional	-0.001

4.3. The spherical_camera Model

Parameter	Label	Presence	Default	Description
shutter_open_time	Shutter Open Time	optional	0.0
shutter_close_time	Shutter Close Time	optional	1.0

4.4. The thinlens_camera Model

Parameter	Label	Presence	Default	Description
shutter_open_time	Shutter Open Time	optional	0.0
shutter_close_time	Shutter Close Time	optional	1.0
film_dimensions	Film Dimensions	required	None
film_width	Film Width	required	None
film_height	Film Height	required	None
aspect_ratio	Aspect Ratio	required	None
focal_length	Focal Length	required	None
horizontal_fov	Horizontal FOV	required	None
f_stop	F-Number	required	8.0
focal_distance	Focal Distance	optional	1.0
autofocus_target	Autofocus Target	optional	0.5 0.5
diaphragm_blades	Diaphragm Blades	optional	0
diaphragm_tilt_angle	Diaphragm Tilt Angle	optional	0.0
diaphragm_map	Diaphragm Map	optional	None
near_z	Near Z	optional	-0.001

5.1. The color Model

Parameter	Label	Presence	Default	Description
color_space	Color Space	required	srgb	Possible values are: ciexyz (CIE XYZ), linear_rgb (Linear RGB), spectral (Spectral), srgb (sRGB).
wavelength_range	Wavelength Range	optional	400.0 700.0
color	Color	required	0.0 0.0 0.0
alpha	Alpha	optional	1.0
multiplier	Multiplier	optional	1.0

6. Built-in EDF Models

6.1. The cone_edf Model

Parameter	Label	Presence	Default	Description
radiance	Radiance	required	1.0
radiance_multiplier	Radiance Multiplier	optional	1.0
exposure	Exposure	optional	0.0	Exposure
angle	Angle	required	90.0
cast_indirect_light	Cast Indirect Light	optional	true
importance_multiplier	Importance Multiplier	optional	1.0
light_near_start	Light Near Start	optional	0.0

6.2. The diffuse_edf Model

Parameter	Label	Presence	Default	Description
radiance	Radiance	required	1.0
radiance_multiplier	Radiance Multiplier	optional	1.0
exposure	Exposure	optional	0.0	Exposure
cast_indirect_light	Cast Indirect Light	optional	true
importance_multiplier	Importance Multiplier	optional	1.0
light_near_start	Light Near Start	optional	0.0

7.1. The generic_environment Model

Parameter	Label	Presence	Default	Description
environment_edf	Environment EDF	optional	None
environment_shader	Environment Shader	optional	None

8. Built-in Environment EDF Models

8.1. The constant_environment_edf Model

Parameter	Label	Presence	Default	Description
radiance	Radiance	required	1.0	Environment radiance

8.2. The constant_hemisphere_environment_edf Model

Parameter	Label	Presence	Default	Description
upper_hemi_radiance	Upper Hemisphere Radiance	required	0.7	Upper hemisphere radiance
lower_hemi_radiance	Lower Hemisphere Radiance	required	0.3	Lower hemisphere radiance

8.3. The gradient_environment_edf Model

Parameter	Label	Presence	Default	Description
horizon_radiance	Horizon Radiance	required	0.3	Horizon radiance
zenith_radiance	Zenith Radiance	required	0.7	Zenith radiance

8.4. The hosek_environment_edf Model

Parameter	Label	Presence	Default	Description
sun_theta	Sun Theta Angle	required	45.0	Sun polar (vertical) angle in degrees
sun_phi	Sun Phi Angle	required	0.0	Sun azimuthal (horizontal) angle in degrees
turbidity	Turbidity	required	1.0	Atmospheric haziness
turbidity_multiplier	Turbidity Multiplier	optional	2.0	Atmospheric haziness multiplier
luminance_multiplier	Luminance Multiplier	optional	1.0	Sky luminance multiplier
luminance_gamma	Luminance Gamma	optional	1.0	Sky luminance gamma
saturation_multiplier	Saturation Multiplier	optional	1.0	Sky color saturation multiplier
horizon_shift	Horizon Shift	optional	0.0	Rotate the sky horizontally by a given number of degrees
ground_albedo	Ground Albedo	optional	0.3	Ground albedo (reflection coefficient of the ground)

8.5. The latlong_map_environment_edf Model

Parameter	Label	Presence	Default	Description
radiance	Radiance	required	1.0	Environment texture
radiance_multiplier	Radiance Multiplier	optional	1.0	Environment texture radiance multiplier
exposure	Exposure	optional	0.0	Environment exposure
horizontal_shift	Horizontal Shift	optional	0.0	Environment texture horizontal shift in degrees
vertical_shift	Vertical Shift	optional	0.0	Environment texture vertical shift in degrees

8.6. The mirrorball_map_environment_edf Model

Parameter	Label	Presence	Default	Description
radiance	Radiance	required	1.0	Environment texture
radiance_multiplier	Radiance Multiplier	optional	1.0	Environment texture radiance multiplier

8.7. The osl_environment_edf Model

Parameter	Label	Presence	Default	Description
osl_background	OSL Background	optional	None

8.8. The preetham_environment_edf Model

Parameter	Label	Presence	Default	Description
sun_theta	Sun Theta Angle	required	45.0	Sun polar (vertical) angle in degrees
sun_phi	Sun Phi Angle	required	0.0	Sun azimuthal (horizontal) angle in degrees
turbidity	Turbidity	required	1.0	Atmospheric haziness
turbidity_multiplier	Turbidity Multiplier	optional	2.0	Atmospheric haziness multiplier
luminance_multiplier	Luminance Multiplier	optional	1.0	Sky luminance multiplier
luminance_gamma	Luminance Gamma	optional	1.0	Sky luminance gamma
saturation_multiplier	Saturation Multiplier	optional	1.0	Sky color saturation multiplier
horizon_shift	Horizon Shift	optional	0.0	Rotate the sky horizontally by a given number of degrees

9. Built-in Environment Shader Models

9.1. The background_environment_shader Model

Parameter	Label	Presence	Default	Description
color	Color	required	0.5
alpha	Alpha	optional	1.0

9.2. The edf_environment_shader Model

Parameter	Label	Presence	Default	Description
environment_edf	Environment EDF	required	None
alpha_value	Alpha Value	optional	1.0

10.1. The frame Model

Parameter	Label	Presence	Default	Description
camera	Camera	optional	None
resolution	Resolution	required	None
crop_window	Crop Window	optional	None
tile_size	Tile Size	required	None
filter	Filter	optional	blackman-harris	Possible values are: blackman-harris (Blackman-Harris), box (Box), catmull (Catmull-Rom Spline), bspline (Cubic B-spline), gaussian (Gaussian), lanczos (Lanczos), mitchell (Mitchell-Netravali), triangle (Triangle).
filter_size	Filter Size	optional	1.5

11. Built-in Light Models

11.1. The directional_light Model

Parameter	Label	Presence	Default	Description
irradiance	Irradiance	required	1.0	Light intensity
irradiance_multiplier	Irradiance Multiplier	optional	1.0	Light intensity multiplier
exposure	Exposure	optional	0.0	Light exposure
cast_indirect_light	Cast Indirect Light	optional	true	If enabled, this light contributes to indirect lighting
importance_multiplier	Importance Multiplier	optional	1.0	Adjust the sampling effort for this light with respect to the other lights

11.2. The max_omni_light Model

Parameter	Label	Presence	Default	Description
intensity	Intensity	required	1.0	Light intensity
intensity_multiplier	Intensity Multiplier	optional	1.0	Light intensity multiplier
decay_start	Decay Start	optional	0.0	Distance at which light decay starts
decay_exponent	Decay Exponent	optional	2.0	Exponent of the light decay function
cast_indirect_light	Cast Indirect Light	optional	true	If enabled, this light contributes to indirect lighting
importance_multiplier	Importance Multiplier	optional	1.0	Adjust the sampling effort for this light with respect to the other lights

11.3. The max_spot_light Model

Parameter	Label	Presence	Default	Description
intensity	Intensity	required	1.0	Light intensity
intensity_multiplier	Intensity Multiplier	optional	1.0	Light intensity multiplier
inner_angle	Inner Angle	required	20.0	Cone distribution inner angle
outer_angle	Outer Angle	required	30.0	Cone distribution outer angle
tilt_angle	Tilt Angle	optional	0.0	Rotate the spot light around its axis; only useful when using the light intensity is textured (gobo)
decay_start	Decay Start	optional	0.0	Distance at which light decay starts
decay_exponent	Decay Exponent	optional	2.0	Exponent of the light decay function
cast_indirect_light	Cast Indirect Light	optional	true	If enabled, this light contributes to indirect lighting
importance_multiplier	Importance Multiplier	optional	1.0	Adjust the sampling effort for this light with respect to the other lights

11.4. The point_light Model

Parameter	Label	Presence	Default	Description
intensity	Intensity	required	1.0	Light intensity
intensity_multiplier	Intensity Multiplier	optional	1.0	Light intensity multiplier
exposure	Exposure	optional	0.0	Light exposure
cast_indirect_light	Cast Indirect Light	optional	true	If enabled, this light contributes to indirect lighting
importance_multiplier	Importance Multiplier	optional	1.0	Adjust the sampling effort for this light with respect to the other lights

11.5. The spot_light Model

Parameter	Label	Presence	Default	Description
intensity	Intensity	required	1.0	Light intensity
intensity_multiplier	Intensity Multiplier	optional	1.0	Light intensity multiplier
exposure	Exposure	optional	0.0	Light exposure
inner_angle	Inner Angle	required	20.0	Cone distribution inner angle
outer_angle	Outer Angle	required	30.0	Cone distribution outer angle
tilt_angle	Tilt Angle	optional	0.0	Rotate the spot light around its axis; only useful when using the light intensity is textured (gobo)
cast_indirect_light	Cast Indirect Light	optional	true	If enabled, this light contributes to indirect lighting
importance_multiplier	Importance Multiplier	optional	1.0	Adjust the sampling effort for this light with respect to the other lights

11.6. The sun_light Model

Parameter	Label	Presence	Default	Description
environment_edf	Bind To	optional	None	If an environment EDF is bound, use the sun angles and turbidity values from the environment
turbidity	Turbidity	required	4.0	Atmospheric haziness
radiance_multiplier	Radiance Multiplier	optional	1.0	Light intensity multiplier
size_multiplier	Size Multiplier	optional	1.0	The size multiplier allows to make the sun bigger or smaller, hence making it cast softer or harder shadows
distance	Distance	optional	149.6	Distance between Sun and scene (millions of km)
cast_indirect_light	Cast Indirect Light	optional	true	If enabled, this light contributes to indirect lighting
importance_multiplier	Importance Multiplier	optional	1.0	Adjust the sampling effort for this light with respect to the other lights

12. Built-in Material Models

12.1. The disney_material Model

Parameter	Label	Presence	Default	Description
surface_shader	Surface Shader	optional	None
edf	EDF	optional	None
alpha_map	Alpha Map	optional	None
displacement_map	Displacement Map	optional	None
displacement_method	Displacement Method	required	bump	Possible values are: bump (Bump Mapping), normal (Normal Mapping).
bump_amplitude	Bump Amplitude	optional	1.0
bump_offset	Bump Offset	optional	0.5
normal_map_up	Normal Map Up Vector	optional	z	Possible values are: z (Blue Channel (Z)), y (Green Channel (Y)).

12.2. The generic_material Model

Parameter	Label	Presence	Default	Description
surface_shader	Surface Shader	optional	None
bsdf	BSDF	optional	None
bssrdf	BSSRDF	optional	None
edf	EDF	optional	None
volume	Volume	optional	None
alpha_map	Alpha Map	optional	None
displacement_map	Displacement Map	optional	None
displacement_method	Displacement Method	required	bump	Possible values are: bump (Bump Mapping), normal (Normal Mapping).
bump_amplitude	Bump Amplitude	optional	1.0
bump_offset	Bump Offset	optional	0.5
normal_map_up	Normal Map Up Vector	optional	z	Possible values are: z (Blue Channel (Z)), y (Green Channel (Y)).

12.3. The osl_material Model

Parameter	Label	Presence	Default	Description
surface_shader	Surface Shader	optional	None
osl_surface	OSL Surface	optional	None
alpha_map	Alpha Map	optional	None

13. Built-in Object Models

13.1. The curve_object Model

13.2. The mesh_object Model

Parameter	Label	Presence	Default	Description
alpha_map	Alpha Map	optional	None

14. Built-in Surface Shader Models

14.1. The ao_surface_shader Model

Parameter	Label	Presence	Default	Description
sampling_method	Sampling Method	required	uniform	Possible values are: cosine (Cosine-Weighted Sampling), uniform (Uniform Sampling).
samples	Samples	required	16
max_distance	Maximum Occlusion Distance	required	1.0

14.2. The constant_surface_shader Model

Parameter	Label	Presence	Default	Description
color	Color	required	0.5
alpha_source	Alpha Source	optional	color	Possible values are: color (Alpha channel of the color), material (Alpha map of the object and/or material).
color_multiplier	Color Multiplier	optional	1.0
alpha_multiplier	Alpha Multiplier	optional	1.0

14.3. The diagnostic_surface_shader Model

Parameter	Label	Presence	Default	Description
mode	Mode	required	coverage	Possible values are: ambient_occlusion (Ambient Occlusion), assembly_instances (Assembly Instances), barycentric (Barycentric Coordinates), bitangent (Bitangents), color (Color), coverage (Coverage), depth (Depth), facing_ratio (Facing Ratio), geometric_normal (Geometric Normals), materials (Materials), object_instances (Object Instances), original_shading_normal (Original Shading Normals), primitives (Primitives), ray_spread (Ray Spread), regions (Regions), screen_space_wireframe (Screen-space Wireframe), shading_normal (Shading Normals), sides (Sides), tangent (Tangents), uv (UV Coordinates), world_space_position (World Space Position), world_space_wireframe (World-space Wireframe).

14.4. The physical_surface_shader Model

Parameter	Label	Presence	Default	Description
lighting_samples	Lighting Samples	optional	1

15. Built-in Texture Models

15.1. The disk_texture_2d Model

Parameter	Label	Presence	Default	Description
filename	File Path	required	None
color_space	Color Space	required	srgb	Possible values are: ciexyz (CIE XYZ), linear_rgb (Linear RGB), srgb (sRGB).

15.2. The memory_texture_2d Model

Parameter	Label	Presence	Default	Description
color_space	Color Space	required	srgb	Possible values are: ciexyz (CIE XYZ), linear_rgb (Linear RGB), srgb (sRGB).

16. Built-in Volume Models

16.1. The generic_volume Model

Parameter	Label	Presence	Default	Description
absorption	Absorption Coefficient	required	0.5
absorption_multiplier	Absorption Coefficient Multiplier	optional	1.0
scattering	Scattering Coefficient	required	0.5
scattering_multiplier	Scattering Coefficient Multiplier	optional	1.0
phase_function_model	Phase Function Model	required	isotropic	Possible values are: henyey (Henyey-Greenstein), isotropic (Isotropic).
average_cosine	Average Cosine (g)	optional	0.0