material Element Reference

Abstract representation of a surface Material, defined without respect to the underlying surface. More...

List of all members.

Attributes
string	bumpMap
	Specifies a path to an image to be applied as a bump map for this material.
ureal_t	bumpIntensity
	Scaling factor for the intensity of the bump map effect.
medium	medium
	Internal medium of shapes to which this material is applied.
filter	filter
	Filter to use for filtering texture map lookups.
ureal_t	repeatU
	Number of times to repeat texture coordinates across this Material in the horizontal direction, u.
ureal_t	repeatV
	Number of times to repeat texture coordinates across this Material in the vertical direction, v.
bsdf	bsdf
	Constant reflectivity model of this material, whose model-specific inputs are allowed to vary across the surface of this material.
emitter	emitter
	Constant emittance model / distribution for this material, whose model-specific inputs are allowed to vary across the surface of this material.

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Detailed Description

Abstract representation of a surface Material, defined without respect to the underlying surface.

There is a loose coupling between Shapes and Materials from the point-of-view of a Material, but all Shapes know about their surface Material. Materials subclass PropertyMap, and it is through this interface that Material properties may be set (ex: diffuse color, texture/bump/color map(s), index of refraction of interior volume, etc.).

Reflectivity, emittance, and sensor response (BSDFs, Emitters, and Sensors respectively) are three properties of a material that are defined at a single point on a surface. A Material encapsulates BSDF, Emitter, and Sensor properties defined over its surface, where specific instances of BSDF, Emitter, and Sensor are allowed to have their inputs vary with respect to position along the surface. In this respect, Materials represent a mapping from surface position to associated BSDF, Emitter, and Sensor functions, where the underlying functions themselves remain constant along the surface, and only the inputs vary among the different instances / surface points. For example, a Material may have a DiffuseBSDF over its entire surface, but a specific DiffuseBSDF instance obtained by getBSDF or implicitly in initSurfacePoint (which fills in the SurfacePoint's BSDF), is allowed to have its kd parameter (diffuse albedo) vary with respect to the given surface point via lookup in an associated kd texture map defined over the UV coordinates of the surface.

Note:

material corresponds to the underlying Milton class 'Material.'

Example usage:

"material": {

// this example material declares a planar area light source

// declare reflectivity (optional)

"bsdf" : {

"type" : "diffuse",

"kd"

: 0.5,

},

// declare emittance (optional)

"emitter" : {

"type" : "oriented",

"power" : [ 80, 80, 80 ],

},

// subnodes to which this material is applied

"transform" : {

"translate" : [ 0, 1, 0 ],

// rotate plane to face downwards towards origin

"rotate" : [ 0, 0, 0, 1, 0, 0, 180 ],

"scale" : [ .75, 1, .75 ],

"plane" : { },

},

},

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Attribute Documentation

string material::bumpMap

Specifies a path to an image to be applied as a bump map for this material.

type	string
optional	true
default	no bump map

ureal_t material::bumpIntensity

Scaling factor for the intensity of the bump map effect.

type	positive real scalar
optional	true
default	5

medium material::medium

Internal medium of shapes to which this material is applied.

type	medium
optional	true
default	air

filter material::filter

Filter to use for filtering texture map lookups.

type	filter
optional	true
default	triangle

ureal_t material::repeatU

Number of times to repeat texture coordinates across this Material in the horizontal direction, u.

type	positive real scalar
optional	true
default	1

ureal_t material::repeatV

Number of times to repeat texture coordinates across this Material in the vertical direction, v.

type	positive real scalar
optional	true
default	1

bsdf material::bsdf

Constant reflectivity model of this material, whose model-specific inputs are allowed to vary across the surface of this material.

type	bsdf
optional	true
default	gray, diffuse

emitter material::emitter

Constant emittance model / distribution for this material, whose model-specific inputs are allowed to vary across the surface of this material.

type	emitter
optional	true
default	null (no emittance)