Full documentation of PSDL.

Photon Scene Description Language

Geometry

• Category: Geometry
• Type: Geometry
• Note: blueprint only

Defining the shape of scene elements.

(no input)

Spherical Geometry

• Category: Geometry
• Type: Sphere
• Note: concrete, based on Geometry

A perfectly round shape centering around origin.

Creation: geometry(sphere)

Inputs	Types	Descriptions
radius	real	Size of the sphere.

Rectangular Geometry

• Category: Geometry
• Type: Rectangle
• Note: concrete, based on Geometry

A rectangular shape on xy-plane. It is centered around origin.

Creation: geometry(rectangle)

Inputs	Types	Descriptions
width	real	Width of the rectangle.
height	real	Height of the rectangle.
texcoord-scale	real	A scaling factor that scales the default-generated texture coordinates.

Triangle Geometry

• Category: Geometry
• Type: Triangle
• Note: concrete, based on Geometry

A single triangle-shaped surface. Please note that using this type of triangle for triangle mesh may induce significant overhead (in terms of memory usage). This is meant for very simple shapes or debug usages.

Creation: geometry(triangle)

Inputs	Types	Descriptions
v-A	vector3	The first vertex coordinates of the triangle.
v-B	vector3	The second vertex coordinates of the triangle, in CCW.
v-C	vector3	The third vertex coordinates of the triangle, in CCW.
uvw-A	vector3	Texture coordinates of the first vertex.
uvw-B	vector3	Texture coordinates of the first vertex.
uvw-C	vector3	Texture coordinates of the first vertex.
n-A	vector3	Normal vector of the first vertex.
n-B	vector3	Normal vector of the second vertex.
n-C	vector3	Normal vector of the third vertex.

Triangle Mesh

• Category: Geometry
• Type: Triangle Mesh
• Note: concrete, based on Geometry

A cluster of triangles forming a singe shape in 3-D space.

Creation: geometry(triangle-mesh)

Inputs	Types	Descriptions
positions	vector3-array	Vertex coordinates of all triangles. Every three vector3s in the array represents a single triangle. The vertices are expected to be given in counterclockwise order.
texture-coordinates	vector3-array	Similar to positions, except that the array stores texture coordinates for each triangle.
normals	vector3-array	Similar to positions, except that the array stores normal vectors for each triangle.

Menger Sponge Geometry

• Category: Geometry
• Type: Menger Sponge
• Note: concrete, based on Geometry

A fractal geometry.

Creation: geometry(menger-sponge)

Inputs	Types	Descriptions
iterations	integer	Number of iterations on the fractal surface detail.

Geometry Soup

• Category: Geometry
• Type: Geometry Soup
• Note: concrete, based on Geometry

A collection of random geometries.

Creation: geometry(geometry-soup)

Inputs	Types	Descriptions
geometries	geometry-array	Array of references to the geometries in the soup.

PLY Polygon Mesh

• Category: Geometry
• Type: Ply
• Note: concrete, based on Geometry

Polygon mesh stored as a .ply file.

Creation: geometry(ply)

Inputs	Types	Descriptions
ply-file	PRI	The .ply file that stores the polygon mesh.

Material

• Category: Material
• Type: Material
• Note: blueprint only

Defines and models the appearance of scene elements.

(no input)

Surface Material

• Category: Material
• Type: Surface Material
• Note: blueprint only, based on Material

(no description)

(no input)

Matte Opaque Material

• Category: Material
• Type: Matte Opaque
• Note: concrete, based on Surface Material

A material model for surfaces with matte look, such as chalk and moon.

Creation: material(matte-opaque)

Inputs	Types	Descriptions
albedo	image	An image or constant color that will be used for describing albedo.
sigma-degrees	image	Roughness in standard deviation of surface orientation (unit: degrees).

Abraded Opaque Material

• Category: Material
• Type: Abraded Opaque
• Note: concrete, based on Surface Material

Able to model surfaces ranging from nearly specular to extremely rough appearances.

Creation: material(abraded-opaque)

Inputs	Types	Descriptions
fresnel	enum	Type of the Fresnel for the conductive interface.
f0	spectrum	Surface reflectance on normal incidence. This value is expected to be given in linear-sRGB space. When this parameter is used, the underlying Fresnel model will be an approximated one (schlick) which is pretty popular in real-time graphics. Also note that F0 already includes the information of ior-outer.
ior-outer	real	The index of refraction outside of this interface.
ior-inner-n	spectrum	The complex index of refraction (real part) inside of this interface.
ior-inner-k	spectrum	The complex index of refraction (imaginary part) inside of this interface.
microsurface	enum	Type of the microsurface of the material.
roughness-to-alpha	enum	Type of the mapping to transform roughness into alpha value.
roughness	real	Isotropic surface roughness in [0, 1], the material will appear to be smoother with smaller roughness value.
roughness-v	real	Similar to the roughness parameter, but is used for anisotropic surface appearances. This value controls the V component of surface roughness. If this value is provided, the roughness parameter is interpreted as the U component of surface roughness.

Abraded Translucent Material

• Category: Material
• Type: Abraded Translucent
• Note: concrete, based on Surface Material

Able to model translucent surfaces with variable roughnesses. Such as frosted glass.

Creation: material(abraded-translucent)

Inputs	Types	Descriptions
fresnel	enum	Type of the Fresnel for the dielectric interface.
ior-outer	real	The index of refraction outside of this interface.
ior-inner	real	The index of refraction inside of this interface.
microsurface	enum	Type of the microsurface of the material.
roughness-to-alpha	enum	Type of the mapping to transform roughness into alpha value.
roughness	real	Isotropic surface roughness in [0, 1], the material will appear to be smoother with smaller roughness value.
roughness-v	real	Similar to the roughness parameter, but is used for anisotropic surface appearances. This value controls the V component of surface roughness. If this value is provided, the roughness parameter is interpreted as the U component of surface roughness.

Full Material

• Category: Material
• Type: Full
• Note: concrete, based on Material

A material model that combines surface and volume properties.

Creation: material(full)

Inputs	Types	Descriptions
surface	material	A surface material.
interior	material	A volume material describing the inside of the surface.
exterior	material	A volume material describing the outside of the surface.

Ideal Substance Material

• Category: Material
• Type: Ideal Substance
• Note: concrete, based on Surface Material

Models a perfectly smooth surface with various physical properties.

Creation: material(ideal-substance)

Inputs	Types	Descriptions
substance	enum	Specifying the physical property/behavior of the surface.
fresnel	enum	Type of the Fresnel for the interface.
ior-outer	real	The index of refraction outside the surface.
ior-inner	real	The index of refraction inside the surface.
f0	spectrum	Surface reflectance on normal incidence. This value is expected to be given in linear-sRGB space. When this parameter is used, the underlying Fresnel model will be an approximated one (schlick) which is pretty popular in real-time graphics.
reflection-scale	spectrum	A scaling factor for reflected energy. Note that this property is only for artistic control and is not physically correct.
transmission-scale	spectrum	A scaling factor for transmitted energy. Note that this property is only for artistic control and is not physically correct.
ior-inner-n	spectrum	The complex index of refraction (real part) inside the metallic interface.
ior-inner-k	spectrum	The complex index of refraction (imaginary part) inside the metallic interface.

Binary Mixed Surface

• Category: Material
• Type: Binary Mixed Surface
• Note: concrete, based on Surface Material

Mixing two surface materials in various ways.

Creation: material(binary-mixed-surface)

Inputs	Types	Descriptions
mode	enum	Specify how two materials are mixed.
material-0	material	The first material that participates the mixing process.
material-1	material	The second material that participates the mixing process.
factor	image	Factor that controls the contribution from each material.

Image

• Category: Image
• Type: Image
• Note: blueprint only

A block of data.

(no input)

Constant Image

• Category: Image
• Type: Constant
• Note: concrete, based on Image

An image that stores constant value. It can be a single scalar, a vector or a color.

Creation: image(constant)

Inputs	Types	Descriptions
value	real-array	A series of values to populate the const image.
color-space	enum	Associated color space of the constant.

Base of Raster Image

• Category: Image
• Type: Raster Base
• Note: blueprint only, based on Image

Common information for raster-based images.

Inputs	Types	Descriptions
sample-mode	enum	Sample mode of the raster image.
wrap-mode	enum	Wrap mode of the raster image.
vertical-wrap-mode	enum	Wrap mode of the raster image in the vertical direction. If this field is specified, the field is treated as the horizontal wrap mode.

Raster File Image

• Category: Image
• Type: Raster File
• Note: concrete, based on Base of Raster Image

Raster-based image file (most common image file formats belongs to this category).

Creation: image(raster-file)

Inputs	Types	Descriptions
image-file	PRI	The image file.

Math Image

• Category: Image
• Type: Math
• Note: concrete, based on Image

This image applies mathematical modifications on other images, such as addition and multiplication.

Creation: image(math)

Inputs	Types	Descriptions
math-image-op	enum	The mathematical operation used.
operand	image	The target image that is going to be operated on.
scalar-input	real	A scalar input for the specified mathematical operation.
input-0	image	First input for the specified mathematical operation.
input-1	image	Second input for the specified mathematical operation.

Black-body Radiation Image

• Category: Image
• Type: Black Body
• Note: concrete, based on Image

An image outputs the value of black-body radiation.

Creation: image(black-body)

Inputs	Types	Descriptions
temperature-k	real	Temperature (in Kelvin) that the black-body radiates on.
is-spectral-radiance	bool	false (default): The energy unit is in radiance; true: The energy unit is in spectral radiance. If “energy” value is specified, this option will have no effect (the user is then responsible for specifying “energy” value in their desired unit).
energy	real	If specified, the resulting radiation will be adjusted (scaled) to the target energy level; otherwise, the true energy level at the temperature will be used.
color-space	enum	The tristimulus color space to use when using the image as a numeric texture. The default is to use the current tristimulus space, and linear-sRGB when the engine is in spectral mode.

Observer

• Category: Observer
• Type: Observer
• Note: blueprint only

A tool for observing the incoming energy of the scene.

(no input)

Oriented Raster Observer

• Category: Observer
• Type: Oriented Raster
• Note: blueprint only, based on Observer

Observers that work by projecting incoming energy in certain ways. Projective observers face the -z axis (+y up) and reside on (0, 0, 0) by default.

Inputs	Types	Descriptions
position	vector3	Position of the observer.
yaw-pitch-row-degrees	vector3	Direction that this observer is looking at in yaw pitch form. yaw: Rotation around +y axis in [-180, 180]; pitch: Declination from the horizon in [-90, 90]; row: Rotation around +z axis in [-180, 180].
direction	vector3	Direction vector that this observer is looking at. No need to be normalized.
up-axis	vector3	The direction vector that this observer consider as upward. No need to be normalized.

Single-Lens Observer

• Category: Observer
• Type: Single Lens
• Note: concrete, based on Oriented Raster Observer

As its name suggests, the lens system in this observer is assumed to have just a single lens. The biggest advantage of it is that depth of field effects are possible under this model. In case of the lens radius is zero, the lens system will be reduced to a pinhole. Images captured by this observer is similar to how a normal human perceives the world but with several simplifications.

Creation: observer(single-lens)

Inputs	Types	Descriptions
lens-radius-mm	real	Radius of the lens in millimeters.
focal-distance-mm	real	The distance in millimeters that the observer is focusing on.
sensor-width-mm	real	Width of the sensor used by this observer in millimeters.
sensor-offset-mm	real	Distance between sensor and light entry (more commonly known as focal length). Will be overridden if FoV is provided.
fov-degrees	real	Field of view of this observer in degrees. If provided, it will be used to adjust sensor offset such that the desired FoV is reached.

Sample Source

• Category: Sample Source
• Type: Sample Source
• Note: blueprint only

Engine component for generating sample values.

(no input)

Runtime Sample Source

• Category: Sample Source
• Type: Runtime
• Note: blueprint only, based on Sample Source

Sample sources that generate samples during render engine execution time.

Inputs	Types	Descriptions
samples	integer	Number of samples that will be generated. This is the number of samples that each data unit (such as a single pixel) will receive, on average.

Uniform Random Sample Source

• Category: Sample Source
• Type: Uniform Random
• Note: concrete, based on Runtime Sample Source

Generating samples in a completely random fashion.

Creation: sample-source(uniform-random)

(no input)

Stratified Sample Source

• Category: Sample Source
• Type: Stratified
• Note: concrete, based on Runtime Sample Source

Generating samples based on engine provided dimensional hints.

Creation: sample-source(stratified)

(no input)

Halton Sample Source

• Category: Sample Source
• Type: Halton
• Note: concrete, based on Runtime Sample Source

Generating samples based on the Halton sequence. The samples generated are somewhat deterministic and can lead to visible patterns if the number of samples is too low.

Creation: sample-source(halton)

(no input)

Visualizer

• Category: Visualizer
• Type: Visualizer
• Note: blueprint only

The main engine component for producing visual content.

(no input)

Frame Visualizer

• Category: Visualizer
• Type: Frame
• Note: blueprint only, based on Visualizer

A visualizer that produces frames, a typical example is an image.

Inputs	Types	Descriptions
rect-x	integer	X coordinate of the lower-left corner of the film cropping window.
rect-y	integer	Y coordinate of the lower-left corner of the film cropping window.
rect-w	integer	Width of the film cropping window.
rect-h	integer	Height of the film cropping window.

Path Tracing Visualizer

• Category: Visualizer
• Type: Path Tracing
• Note: concrete, based on Frame Visualizer

Render frames with common path tracing methods.

Creation: visualizer(path-tracing)

Inputs	Types	Descriptions
scheduler	enum	Scheduler for rendering, affect the order of rendered regions.
estimator	enum	The energy estimating component used by the renderer.
sample-filter	enum	Sample filter for the film sampling process.

Option

• Category: Option
• Type: Option
• Note: concrete

Options that control engine runtime behavior.

Creation: option(option)

(no input)

Render Session

• Category: Option
• Type: Render Session
• Note: blueprint only, based on Option

Settings for how to perform a render operation.

Inputs	Types	Descriptions
session-name	string	Name of this render session.
num-workers	integer	Number of worker threads for the rendering operation.

Single Frame Render Session

• Category: Option
• Type: Single Frame Render Session
• Note: concrete, based on Render Session

Information regarding the rendering process of a single frame.

Creation: option(single-frame-render-session)

Inputs	Types	Descriptions
frame-size	vector2	Width and height of the frame in pixels.
visualizer	string	Name of the visualizer resource to use.
observer	string	Name of the observer resource to use.
sample-source	string	Name of the sample source resource to use.
top-level-accelerator	enum	Acceleration structure used on the top level geometries.

Object

• Category: Object
• Type: Object
• Note: blueprint only

General object that may refer to any type.

(no input)

Actor

• Category: Actor
• Type: Actor
• Note: blueprint only

Represents an entity in the scene. Every entity that participates in a scene is an actor.

(no input)

Physical Actor

• Category: Actor
• Type: Physical
• Note: blueprint only, based on Actor

An actor that is visible and can be transformed.

Inputs	Types	Descriptions
position	vector3	Position of the entity.
rotation	quaternion	Rotation of the entity
scale	vector3	Scale of the entity.

Operation: translate, callable on actor(physical) and its derivations

Moves the actor away from the original location with a specified amount.

Inputs	Types	Descriptions
amount	vector3	The amount to move on each axis.

Operation: rotate, callable on actor(physical) and its derivations

Rotates the actor along an axis with a specified amount.

Inputs	Types	Descriptions
axis	vector3	The axis for rotation.
degrees	real	The amount of the rotation, in degrees.
rotation	quaternion	Specify the rotation with a quaternion directly.

Operation: scale, callable on actor(physical) and its derivations

Enlarges or shrinks the actor with some specified amount.

Inputs	Types	Descriptions
amount	vector3	The amount to scale on each axis.

Model Actor

• Category: Actor
• Type: Model
• Note: concrete, based on Physical Actor

An actor that has a certain 3-D shape in the scene.

Creation: actor(model)

Inputs	Types	Descriptions
geometry	geometry	A geometry that represent this actor’s shape.
material	material	A material that describes this actor’s surface appearance.
motion	motion	Movement of this actor.

Dome Actor

• Category: Actor
• Type: Dome
• Note: blueprint only, based on Physical Actor

A large energy emitting source encompassing the whole scene.

Inputs	Types	Descriptions
energy-scale	real	A non-physical scale factor for artistic purpose.

Image Dome Actor

• Category: Actor
• Type: Image Dome
• Note: concrete, based on Dome Actor

Using a background image to represent the energy emitted from far away.

Creation: actor(image-dome)

Inputs	Types	Descriptions
image-file	PRI	An image describing the energy distribution.

Preetham Dome Actor

• Category: Actor
• Type: Preetham Dome
• Note: concrete, based on Dome Actor

Using Preetham model to generate absolute energy from sky.

Creation: actor(preetham-dome)

Inputs	Types	Descriptions
turbidity	real	Turbidity of the atmosphere.
standard-time-24h	real	Standard time in 24H.
standard-meridian-degrees	real	Standard meridian in degrees.
site-latitude-degrees	real	Site latitude in [-90, 90] degrees (“+” implies N and “-“ implies S).
site-longitude-degrees	real	Site longitude in [0, 360] degrees (with prime meridian being 0)
julian-date	integer	The day of the year as an integer in the range [1, 366].
sun-phi-theta-degrees	vector2	Directly specify sun position in the sky in spherical coordinates. Note that this option may not be physically correct since not every position in the sky is possible for the sun given a location on Earth.

Light Actor

• Category: Actor
• Type: Light
• Note: blueprint only, based on Physical Actor

The source of all energy emitting entity in the scene.

(no input)

Geometric Light Actor

• Category: Actor
• Type: Geometric Light
• Note: blueprint only, based on Light Actor

Energy emitters that come with a physical geometry.

(no input)

Area Light Actor

• Category: Actor
• Type: Area Light
• Note: blueprint only, based on Geometric Light Actor

This type of light source has a finite area. Energy is allowed to emit as long as the emitting source is within the area.

Inputs	Types	Descriptions
color	spectrum	The color of this light source.
watts	real	Energy emitted by this light source, in watts.

Model Light Actor

• Category: Actor
• Type: Model Light
• Note: concrete, based on Geometric Light Actor

A light source that emits energy from the surface of a geometry. A surface material model can also be given to describe its surface appearance.

Creation: actor(model-light)

Inputs	Types	Descriptions
geometry	geometry	A geometry that defines the surface energy is going to emit from.
material	material	A material that describes this source’s surface appearance.
emitted-radiance	image	An image that describes the emitted radiance across the surface.
back-face-emit	bool	Whether the energy should emit from the back face of the geometry.

Point Light Actor

• Category: Actor
• Type: Point Light
• Note: concrete, based on Area Light Actor

Power emitting source from a small but not infinitesimal region. Resembling a small light bulb.

Creation: actor(point-light)

(no input)

Rectangular Light Actor

• Category: Actor
• Type: Rectangle Light
• Note: concrete, based on Area Light Actor

This type of light emits energy from a rectangular shape.Note that energyis only allowed to emit from one side of the rectangle, not both sides.

Creation: actor(rectangle-light)

Inputs	Types	Descriptions
width	real	The width of the rectangle.
height	real	The height of the rectangle.

Spherical Light Actor

• Category: Actor
• Type: Sphere Light
• Note: concrete, based on Area Light Actor

This type of light emits energy from a spherical shape.

Creation: actor(sphere-light)

Inputs	Types	Descriptions
radius	real	The radius of the sphere.

IES-Attenuated Light Actor

• Category: Actor
• Type: Ies Attenuated Light
• Note: concrete, based on Light Actor

Attenuating energy emitting strength of a light with an IES profile.

Creation: actor(ies-attenuated-light)

Inputs	Types	Descriptions
source	actor	The light source that will be attenuated.
ies-file	PRI	The IES file.

Accelerator

Denotes acceleration structure types.

Entries	Descriptions
(empty)	(no description)
brute-force	(no description)
bvh	(no description)
kd-tree	(no description)
indexed-kd-tree	(no description)

Estimator

Type of energy estimation algorithms.

Entries	Descriptions
(empty)	(no description)
bvpt	Backward path tracing.
bneept	Backward path tracing with next event estimation.
bvptdl	Backward path tracing, evaluate direct lighting only (single bounce)

Sample Filter

The type of filter used during the sampling process.

Entries	Descriptions
(empty)	(no description)
box	The box filter. Fairly sharp, fast to evaluate, but can have obvious aliasing around edges.
gaussian	The Gaussian filter. Gives smooth results, slower to evaluate and can sometimes result in blurry images.
mn	The Mitchell-Netravali filter. Smooth but remains sharp around edges.
bh	The Blackman-Harris filter. A good compromise between smoothness and sharpness.

Sample Mode

Controls how the image will be sampled.

Entries	Descriptions
(empty)	(no description)
nearest	(no description)
bilinear	(no description)
trilinear	(no description)

Wrap Mode

Controls how the image will be sampled when texture coordinates is not within the range [0, 1].

Entries	Descriptions
(empty)	(no description)
repeat	(no description)
clamp-to-edge	(no description)
flipped-clamp-to-edge	(no description)

Color Space

Marks color space information of input values.

Entries	Descriptions
(empty)	(no description)
LSRGB	(no description)
SRGB	(no description)
ACES	(no description)
SPD	(no description)

Color Usage

Marks color usage information of input values.

Entries	Descriptions
(empty)	(no description)
RAW	(no description)
EMR	(no description)
ECF	(no description)

Math Image Op

The mathematical operation used on images.

Entries	Descriptions
ADD	(no description)
MUL	(no description)

Interface Fresnel

Controls the Fresnel model used.

Entries	Descriptions
(empty)	(no description)
schlick	An approximative model developed by Schlick.
exact	The full-form Fresnel formula.

Roughness To Alpha

How roughness value will be mapped to alpha, a value that controls surface normal distribution function.

Entries	Descriptions
(empty)	(no description)
equaled	Directly assign roughness value as-is to alpha.
squared	Mapping for a perceptually linear roughness. According to a course note in SIGGRAPH 2014: Moving Frostbite to Physically Based Rendering 3.0, P.68, they concluded that a squared mapping gives slightly better distribution of the profiles (blur amount) among all mip levels in the case of pre-integrated diffuse IBL maps.
pbrt-v3	The mapping used in PBRT-v3.

Ideal Substance

Type of the physical behavior of a perfectly smooth surface.

Entries	Descriptions
absorber	(no description)
dielectric-reflector	(no description)
metallic-reflector	(no description)
transmitter	(no description)
dielectric	(no description)

Surface Material Mix Mode

Specify how surface materials are mixed.

Entries	Descriptions
lerp	(no description)