.paramset format

id

The unique identifier of the parameter set.

Non-negative integer

name

The name of the parameter set.

String

clusterSize

The size of an input cluster, in your modelling units. If you change outputPixelSize, change clusterSize also. As a guide, clusterSize is almost always in the range of 1--4 times the outputPixelSize. Clusters much larger than this result in light being smeared across the output pixels, whereas smaller values do not significantly increase quality (as they have to be averaged for the final output pixel) but can cause unnecessary increases in time and memory footprint.

Performance impact

This controls the resolution at which Enlighten stores and can transfer input light. Like outputPixelSize, it is a linear parameter. Typically, it can be slightly larger than outputPixelSize without significantly reducing final quality, although this depends on the kinds of lighting environments you wish to use. Small, bright light sources will require a smaller clusterSize for Enlighten to capture them accurately.

Positive float (default 250)

 
outputPixelSize

The desired width of an output pixel, in your modelling units. This is applied to each instance of an IPrecompInputGeometry in this system. A geometry can override this value by setting the outputPixelSize in the .geom file, or, if you want a given geometry to have a very specific packed size, the atlasSizeOverride attribute instead.

Performance impact

This parameter directly controls the size of the output lightmaps. It is a linear parameter, so doubling outputPixelSize will result in an approximately fourfold increase in the number of output pixels. Enlighten memory and performance scale linearly with the number of output pixels. Because the Enlighten output textures contain only indirect light, good results can be obtained with extremely low pixel counts; indirect light is usually very low frequency in nature.

Positive float (default 100)

backFaceTolerance

The percentage of a ray origin's rays that must hit front faces to be considered usable. The precompute computes visibility from ray origins to clusters, but attempts to reject ray origins that are inside geometry. If the percentage of rays shot from a ray origin is less than backFaceTolerance, the ray origin is marked invalid and not used for radiosity computation. For example, if backFaceTolerance is 0.0, the ray origin is rejected only if it sees nothing but backfaces. If 1.0, the ray origin is rejected if it has even one ray that hits a backface. This setting can help control light leaking from authoring, but should be considered in the context of your mesh authoring workflow. Preventing the rejection of ray origins by setting a value of 0.0 (the default) will ensure Enlighten does not incorrectly reject ray origins due to open-backed or single-sided geometry. However, if the majority of your meshes are closed so visible backfaces are rare, a positive value can reduce light leaking or darkening, particularly from intersecting geometry.

Positive float (0.0--1.0, 
default 0.9)

 environmentResolution

The resolution for each face of the environment map. The default resolution is 2, effectively resulting in 2 x 2 = 4 values per face. Increasing the environment resolution will improve the quality of lighting from the environment, although higher resolutions (e.g. 32 or 64) have diminishing returns. Values less than or equal to 16 are advisable. Increased resolution can increase the runtime memory footprint and update cost.

Power of 2(min 1, max 64, default 2)

samplesPerCluster

The number of input lighting samples (duster points) per cluster. Typically between 16 and 64 depending on the desired input lighting accuracy. This parameter is analogous to anti-aliasing in rendering. Higher values provide greater anti-aliasing when capturing the input lighting for the radiosity solver, providing greater accuracy and stability under changing lighting conditions. If a sample count is sufficiently high to capture the input lighting then further increases will not produce a quality improvement. Therefore, where performance is a concern, this value should be set as low as possible without introducing lighting instability, usually seen as flickering when lights move. Reducing the sample count will improve the performance of the input lighting stages of the runtime, but will have no performance impact on the solver stages.

Positive integer (multiple of 4, 
maximum 512, 
default 32)

chartBasedLeafClustering

Whether to use chart boundaries if performing "traditional" clustering. When this is enabled clusters are initially confined to charts. This resolves light leaking between geometry belonging to different charts. This feature works best on scenes with few large charts.

Boolean (default false)

computeClusterProbeSampleOffsetData

Whether to compute the offsets data for sampling probes when using the quad transparency feature. This feature is useful for adding limited support for destruction of lightmapped geometry. See Static destruction.

Boolean (default true)

 computeRayOriginOutput

Whether to generate ray origins debug data. When true, data is generated that allows you to view the ray origins used to compute the radiosity in your scene. In GeoRadiosity, setting this parameter to true enables the Ray Origins Chart Renderer mode.

Performance impact

Enabling this mode increases the memory footprint. In some cases, you may get an 'out of memory' error, especially when using 32-bit versions.

Boolean (default false)

directionalIrradiance

Whether to generate directional irradiance output. Controls whether the precompute generates the data required for computing directional irradiance at run time. This is an optional extra output from the irradiance solver which contains the dominant direction of the incoming light for each output pixel. If no directional irradiance data is precomputed and yet directional output is requested, Enlighten returns an error. This parameter only has an effect when voxelBasedLeafClustering is set to false.

Boolean (default true)

dependencyIncludedSystemDistance

The bounding box of the system will be expanded by this value when performing tests to see which of the systems should be fully represented in the ray tracer and which should be approximated by their bounding boxes. A value of 0 causes all the systems to be fully represented.

Non-negative float (default 0)

dependencyVisibilityThreshold

Do not consider a system as a dependency if its visibility is smaller than the threshold. Specify a value of 0to accept systems with any visibility.

Float (min 0, max 1, default 0.015)

dependencyLocalityDistance 

Controls the maximum distance, in world units, at which a given system is considered local. A value of -1 results in no systems being considered local.  

Float (default 4.0) 

clusterTolerance

Controls the strictness of the voxel decimation during clustering. 0.0means the geometry is voxelised strictly. This parameter only has an effect when voxelBasedLeafClustering is set to true.

Positive float (0.0--1.0)

directionalVisibilityDirectionsPerByte

Number of visibility samples to store per byte for precomputed directional visibility. The default value is 4 (2 bits per direction). Valid values are 1, 2, 4and 8. 8 produces the best compression, 1 the best quality. 4produces the best size / quality balance.

Integer (1,2,4,8, 
default 4)

directionalVisibilitySlices

Number of vertical sphere slices for precomputed directional visibility storage. The number of sampled visibility directions will be roughly the square of this number. Defaults to 27(875 sampled directions).

Integer (2--64, default 27)

edgeStitching

Whether to stitch pairs of edges together. When true, Enlighten identifies the pair of edges that should be stitched together, and produce radiosity which is as smooth as possible across the seam. This parameter applies only to straight edges which run horizontally or vertically along chart boundaries in the atlas; the method is designed to work with rectangles which are axis-aligned in UV space. Therefore, if you map your charts carefully it will produce seamless radiosity on cylinders.

Boolean (default false)

alignedEdgeStitching

Whether to use aligned edge stitching. When true, Enlighten identifies the pair of edges that should be stitched together, and produce radiosity which is a smooth as possible across the seam. This parameter applies only to straight edges which run horizontally or vertically along chart boundaries in the atlas and also requires that both side of the edge have the same number of Enlighten light map pixels along the edge. Furthermore, the stitching is performed using the one-to-one mapping of pixels to ensure that stitching is only performed on these pairs.

Boolean (default false)

edgeStitchingDistanceMultiplier

Defines the maximum distance between edges for them to be stitchable, as multiplier of outputPixelSize. Relevant only if edgeStitching is set to true.

Performance impact

This parameter controls the distances over which Enlighten tries to smooth out potential lighting seams. This smoothing process costs memory and time, so this value should be small, hence the default value of 0.3.

Positive float (default 0.3)

importance

A relative importance multiplier for this system in the global light transport step. The default value is 1.0. Higher values should only be used for area light geometry in its own dedicated system (which is known to be a bright source of illumination at precompute time). Setting a high importance will ensure that the area light geometry is retained during the light transport compression step. If you use a high importancemultiplier, you should also ensure that area lights have as few clusters as possible. If the area light has a constant colour, only one cluster is required. This can be achieved by setting voxelBasedLeafClustering="false"and numClusters="1".

Non-negative float (default 1.0)

includeProjectedPointData

Whether to build and include projected duster points for accurate GPU visibility. This feature stores additional duster points for different versions of the geometry, so you can update the duster positions dynamically.

Boolean (default false)

 irradBudget

For every pixel in the output lightmap, Enlighten creates a compressed list of which parts of the scene the pixel can see (and thus transfer light from). The irradBudgetparameter specifies how many of these "form factors" are stored per output pixel for the purpose of creating irradiance lightmap values. Larger budgets give higher indirect lighting "quality" (that is, there is more detail stored about which surfaces transfer light to each pixel). Very low values create "averaged out" radiosity. Setting the value to 0 disables irradiance output (so it is not possible to create an irradiance lightmap at runtime) — if you do this, you should set the irradQuality parameter to its lowest value of 16.

Performance impact

irradBudget controls the amount of data about its lighting environment that Enlighten stores per pixel. As such, the generated Enlighten data scales close to linearly with this budget (but not perfectly, because there are other memory overheads). The higher the budget, the more detail there will be in the final indirect light output. However, Enlighten will take correspondingly more memory and computation time. A minimum budget of 32generally produces acceptable results.

Positive integer (Default 64, 
minimum 1, 
maximum 512[not recommended]).

irradQuality

The number of rays to cast for computing irradiance form factors.

Integer (power of 2, min 16, max 131072)

maxStitchingAngle

Maximum angle between normals for charts to be stitchable. In radians for the HLBS, a dot-product in the low-level API.

Performance impact

This parameter controls the angular changes over which Enlighten tries to smooth out potential lighting seams. The smoothing costs memory and time, so the value should be small. Large values can result in large increases in memory and execution time, because they force Enlighten to smooth output across a large set of seams.

Positive float, (default 0.1 radians 
[~5.7 degrees])

maxPixelStitchingAngle

Maximum angle between normals for pixels to be stitchable. In radians for the HLBS, a dot-product in the low-level API. This parameter controls the number of rays to cast to determine form factor values. The more you use, the better your initial quality before the data reduction. The fewer rays you use, the more noise is introduced (that is, lighting discontinuities; obvious differences between nearby pieces of geometry which you would expect to receive similar lighting.)

Positive float (default PCQ_MEDIUM
[8192 in the HLBS])

maxSamples

Maximum number of input samples for a system. Overrides the calculation of clusterSize * samplesPerClusterand sets an absolute maximum for the number of duster points.

Integer 1--262144

maxSolutionSize

The maximum size of an output system, in pixels.

2-element vector

minSamples

Minimum number of input samples for a system. Overrides the calculation of clusterSize * samplesPerClusterand sets an absolute minimum for the number of duster points.

Integer (1--262144)

minSolutionSize

The minimum size of an output system, in pixels.

2-element vector

numClusters

Set the number of clusters directly. Overrides the clusterSize calculation.

Positive integer

pixelStitching

Whether to use pixel stitching.

Boolean (default true)

projectedPointTriThickness

The thickness of a triangle in worldspace, for use with the ray 'push through' feature when creating projected point data. This value is the distance to step in order to step over a triangle, and is affected by the choice of modelling units in your world. You should not need to change this value under most circumstances. The default is a sensible small epsilon. Cannot be zero.

Float (>0)

projectedPointMaxPushThroughDistance

The maximum world space distance to search in front of a duster point to 'push through' small nearby geometry. This feature can be helpful in producing a better projected point data set in some scenarios. As a guide, similar values to your output pixel size or cluster size should produce reasonable results. Too small a value will have little effect, and too large a value may move points too far from their original locations. You should not need to change this value under most circumstances. The default is 0, which disables this feature.

Float (>0, default 0)

safe16BitClustering

Whether to cap the number of clusters created during the precompute. Ensures that clustering creates no more than 65535 clusters, such that a cluster index will fit in an unsigned integer, which is a runtime requirement.

Boolean (default false)

stitchingDistanceMultiplier

Defines the maximum distance between charts for them to be stitchable, in modelling units. The default of 0.3 gives a maximum chart stitching distance of 0.3 x outputPixelSize.

Performance impact

This parameter controls the distances over which Enlighten tries to smooth out potential lighting seams. This smoothing process costs memory and time, so this value should be small, hence the default value 0.3.

Positive float (default 0.3)

systemGenerationVoxelSizeInPixelSizeUnits

Size of voxels (in output pixel size units) used in voxel based automatic system generation.

Float (default 40)

validOverhangDistance

Mesh projection. Controls the number of pixels that a detail chart should be allowed to overhang the target chart before we consider the overhang to be 'naughty' and appear in the DoDebugColouring output. Zero or negative numbers are valid and imply no overhang is valid.

Integer (default 1)

viewVoxelMultiplier

Size of voxel grid to use for precompute optimisation. This parameter controls how aggressively Enlighten compresses the precomputed data. The parameter value represents the scale at which the precompute considers neighbouring pixels to be "similar".

Performance impact

It is recommended that you set this parameter to 4 (making a voxel four times the output pixel size) for best quality/memory/performance trade-off. Values less than 4 will substantially increase the precompute memory requirements and solve time, for an insignificant gain in output quality.

Positive float

voxelBasedLeafClustering

Use voxel-based clustering to generate leaf clusters. The voxel-based leaf clustering algorithm attempts to decimate geometry along visibility boundaries. It usually produces better results than "traditional" clustering for scenes where meshes intersect each other, and is recommended for scenes with complex geometry that contains many small triangles. To turn it off and use the traditional clustering (the default up to Enlighten 2.16), set this parameter to false.

Boolean (default true)

requiresTerrainLODs

Whether to generate terrain LODs for this system.

Boolean (default false)

requiresTerrainPackingPadding

For terrain systems, decide if system packing should add a half pixel padding around the final atlas. This option does not affect systems that have requiresTerrainLODs set to false. Setting this option to false will disable pixel stitching for this system. All instances in the system should be the same size in terrain UV space, must not overlap, and must be arranged in a uniform grid.

Boolean (default true)

numTerrainLODLevels

For terrain systems, the number of terrain LODs to generate for this system. This option does not affect systems that have requiresTerrainLODs set to false. Setting this option to -1 will generate as many as possible. 

Integer (default -1)

excludeEnvironmentInPrimaryBounce

Whether to exclude the environment form factors from the lightmap solve data. 

Boolean (default false)