RAYTRACE

OPTION: Raytrace, None

Activate the ray casting in the ray casting is a pre-requisite for all ray-tracer lighting calculations.

 HDR

OPTION: Disabled, Half Float, Full Float

Enable or disable the HDR rendering pipeline for the specified window.

HDR is directly performed using the hardware capabilities if the hardware has the appropriate blending functions available. Half float HDR consumes less memory than full float HDR (50% less), but has a lower accuracy resulting of 16 bits half floating point values being used to store color components.

SHADOW MAP DEPTH

OPTION: [integer: 0 to Infinite]:

Defines the rendering depth for which shadow maps are applied on scene elements. A depth of 2 enables shadow maps to generate shadows in a reflection image for example.

SHADOW MAP TRANSPARENCY

OPTION: [Boolean: false, true].

Defines the behavior of shadow mapping versus transparent objects. Because shadow mapping is a shadowing method based on the distance of an occluder from the light source, transparent objects cast black shadows and the amount of transparency can't be considered in the shadowing. This option is used to change this behavior. Whenever set to true, shadow maps will ignore all transparent objects that won't cast shadows anymore.

POLYGON FILL MODE

OPTION : Filled, Lines Points

Defines the polygon fill mode (points, line, filled) for all rendered geometries that are sent to the rendering for the viewpoint that has the given option value.

Filled is used to render triangles as filled polygons. Lines is used to render triangles as only edges and Points is to render triangles as only their three definition vertices.

RAY AREA SHADOW SPACING

OPTION: [integer: 1 to Infinite].

This is the average screen size distance in pixels between two samples used to sample area shadows for the GPU ray-tracer.

RAY AREA SHADOW SPREAD

OPTION: [integer: 1 to Infinite].

This is the coverage factor of GPU area shadow samples on screen. A larger spread value generates more blurry shadows while a smaller value tends to generate sharper shadows.

POST PROCESS

OPTION: Tone, None

Specifies Whether tone mapping will be used post render.

TONE MAPPING IGNORE BACKGROUND

OPTION: [Boolean: false, true].

This option lets the user control whether the contribution of the background images or clear color is considered during the tone mapping calculations or not. If the option is enabled, all pixels of the image that are viewing the background are discarded during tone mapping calculations: they don't have any impact on the image luminance and their colors are not modified. If the option is disabled, the VRL's clear color or background images will participate to the tone mapping process, both in luminance calculations and tone mapping.

Note: that this option is not supported if the tone mapping is performed by the GPU and if the engine anti-aliasing is activated at the same time. In this specific configuration, an aliasing border may be visible in the resulting image.

 LIGHT CUTOFF

[double 0.0 to Infinite].

This value defines the minimal lighting intensity a light must emit to be taken into consideration. This parameter helps improve rendering performances in environments where many lights are set. In such environments, it's not rare to see that many lights have a negligible influence over the shading at a given point. This cutoff value helps the engine discard negligible lights, whose color contribution to the shaded point is below the cutoff value.

See details on this option here: Light cutoff option.

Please note that this value is empirical and arbitrary: it's an absolute intensity cutoff threshold applied to the contribution of a single light, regardless of its environment. In physical HDR environments, the real contribution of a physical light goes infinitely far away. Therefore, if the cutoff is set too high in dark scenes, the application of tone mapping can reveal the light cutoff as a smooth frontier between lit and non-lit areas.

The cutoff works for both physical and non-physical lights. Very small cutoff values can be ignored for non-physical lights rendered on the GPU to preserve some numerical accuracy in the decay calculations performed by rendering shaders.

ENABLE GLOSSY EFFECTS

OPTION: [Boolean: false, true].

The value of this option lets the user to enable or to disable the calculation of glossy ray-traced effects. When off, whatever may be specified by ray-tracer shaders, only one reflection ray and only one refraction ray is fired to render reflection and refraction effects.

RAY ENABLE AREA SAMPLING

OPTION: [Boolean: false, true].

The value of this option lets the user enable or disable the calculation of area light sampling effects. If turned off, then all area lights are replaced by point lights using one single sample. This result in faster lighting and shadowing for example suitable for all pre-visualization purposes.

SHADOWS

OPTION: [integer: 1 to Infinite].

Activates shadow casting for all lights that can cast ray-traced shadows when the specified value is greater than or equal to 1. Activation of shadows forces the activation of the primary ray option. The value of this option indicates the depth of the shadow casting process in the ray-tracing tree.

REFLECTIONS

OPTION: [integer: 1 to Infinite].

Activates the calculation of ray-traced reflections for objects that can reflect light when the specified value is greater than or equal to 1. Activation of reflection forces the activation of the primary ray option. The value of this option indicates the depth of the reflection calculation process in the ray-tracing tree.

REFRACTIONS

OPTION: [integer: 1 to Infinite].

Activates the calculation of ray-traced refractions for objects that are refractive. Activation of the refractions forces the activation of the primary ray option. The value of this option indicates the depth of the refraction calculation process in the ray-tracing tree.

TRANSPARENCY

OPTION: [integer: 1 to Infinite].

Activates the calculation of ray-traced transparencies for objects that are transparent. Activating this option does not force the activation of the primary ray option. The value of this option indicates the transparency depth that'll be rendered for transparent objects.

REFRACTIONS BACK

OPTION: [Boolean: false, true].

When this option is off, the last refractive rays of the rendered ray- tree pass through all refractive objects to only hit opaque objects. For example, if we consider a refractive surface sphere over an opaque ground, and render that scene with a refraction depth set to one, then refractive rays will show the inner face of the sphere if the option is set to true, or they'll show the background if the option is set to false. Disabling this option results in better looking images - however with fake refraction rays for the last depth - whenever there's not enough refraction depth to get through all refractive layers.

MAX THREADS

OPTION: [integer: 1 to Infinite].

The Red engine ray-tracer uses every processor available in the host computer for its rendering. This option can be used to clamp this number to a maximal number of threads running in parallel for the ray- tracer, so that some CPU bandwidth can be reserved for other tasks.

 CUTOFF

[double 0.0 to 1.0].

The value of this option is used as input for the ray-tracer to set the minimal intensity of a ray that is considered as having a valid contribution to the final image. Note that a 0.0 cutoff value removes all optimization effects that can be related to using a cutoff. The smallest meaningful cutoff value is at 0.005.

ANTI-ALIASING SAMPLES RATE

 OPTION: [integer: 1 to Infinite].

ENABLE CAUSTICS

OPTION: [Boolean: false, true].

Activate the calculation of caustics for transparent and reflective objects.

Note: that the generation of caustics depends also on the setup of the object materials and the lights.

Caustics are supported by physical lights only.

CAUSTICS SAMPLING RATE

OPTION: [integer: 0 to 100000].

Set the sampling rate of the caustics photons. The total number of caustics photons for the whole scene is the squared value of the sampling rate (default is 1000x1000 photons).

CAUSTICS SEARCH RADIUS

OPTION: [double: 0.0 to Infinite]. = n

When rendering caustics, the n nearest photons from the point being shaded are queried. This option defines the radius of the search area around that point in scene units. The bigger the radius, the smoother the caustics.

GI

OPTION: [Boolean: false, true].

Enable or disable Global Illumination rendering.

GLOSSY SAMPLING RATE

OPTION: [integer: 0 to Infinite].

Set the number of samples to be taken while sampling glossiness (reflection or refraction). A value of 0 means that the number of samples set to each material is taken. Any other positive values overwrite the materials settings. The real number of samples taken is the square of the option value. For example, if the option is set to 4, 16 samples will be taken.

LIGHTS SAMPLING RATE

OPTION: [integer: 1 to Infinite].

Set the number of samples to be taken while sampling scene lights. A value of 0 means that the number of samples set to each light is taken. Any other positive values overwrite the lights settings. The real number of samples taken is the square of the option value. For example, if the option is set to 4, 16 samples will be taken.

DISPLACEMENT

OPTION: [Boolean: false, true].

Activate software ray-tracer displacement mapping calculations when enabled. If the option is turned on (default) then displacement maps  are used to modify the rendered geometries. If the option is turned off, then no displacement occurs.

FORCE TRANSPARENCY

OPTION: [Boolean: false, true].

This option controls the behavior of the ray-tracer vs. the number of transparency layers that are rendered. By default, this option is disabled so that when a primary ray hits an opaque surface, its propagation is stopped. Turning this option on let the software ray-tracer pursue the propagation of a ray, even behind opaque surfaces. The need to see behind opaque surfaces arise in rendering configurations that are using a non-natural depth buffer setup. For example, rendering methods to see backward edges, section cutting, custom depth ordering, or material priorities are rendering setups that may use an exotic depth buffer setup.

CAUSTICS SEARCH COUNT

OPTION: [integer: 0 to 4096].

Number of photons used for the caustics estimation. The photons search is limited by the value of CAUSTICS SEARCH RADIUS but if more than CAUSTICS SEARCH COUNT are found, only the CAUSTICS SEARCH COUNT nearest photons will be used to estimate caustics.

If the option is set to 0 then all the valid photons inside the search radius will be used to compute the caustics estimate.

Use GPU

OPTION: [Boolean: false, true].

If on the GPU will be used for the ray tracing in the render, if available.

RAY USE EMBREE

OPTION: [Boolean: false, true].

Intel Embree is a collection of ray casting methods. Thanks to its careful handling of SSE instruction sets, it can provide an acceleration ratio between x1.2 and x2 to the rendering of images. However, it does not currently support lot of RED features: double precision matrices and geometries, lines, displacement...

When the option is turned on, the Embree ray-caster is used only for triangle-based geometries in 32bit float precision (vertex channel). Other types of geometries or geometries using higher precision vertex channels are still processed using the RED ray-casting mechanism. Please note that for geometries processed by Embree, the transformation matrices are casted to 32bit float (which may result in a loss of accuracy). If the option is off, the whole data is processed using the RED ray-casting algorithms. If GPU-based ray-tracing is used, the option value is automatically ignored and considered as false.

ERROR

OPTION: [double 0.001 to 1000.0] indicates the error tolerance of the global illumination solution.

The error is inversely proportional to the global illumination precision. A good choice is too leave the error to its default value

Decreasing this error would enhance the final global illumination quality but at the price of a bigger memory consumption and a longer rendering time.

ESTIMATOR SAMPLING RATE

OPTION: [integer 1 to 65535  indicates the squared root of the number of rays used to compute the estimator.

This is the sampling rate of the estimator, i.e the squared root of the total number of rays that will be traced to compute the indirect illumination estimator (first GI pass). You can increase this value for a better estimator convergence but the default value will be good most of the time.

CACHE INTERP SAMPLES COUNT

OPTION: [integer: 1 to Infinite].

Indicates the number of samples taken while estimating the indirect illumination using.

This number is used after the global illumination cache computation, during the rendering phase. It influences the smoothness of the rendered indirect illumination. The bigger the interpolation samples count is, the smoother the result will be (meaning that small details will be lost). If a null or negative value is set, a value of 1 will be automatically assumed.

CACHE PASSES COUNT

OPTION: [integer -127 to 127]

Indicates the number of indirect illumination cache refinement passes if positive; if negative, it is interpreted as a minimum convergence threshold.

The indirect illumination cache is built by iteratively refining an initial set of irradiance samples taken into the scene. The initial set a density proportional to the ERROR value. Then a fixed or variable number of refinement passes are processed to locally refine the cache following scene geometric and/or lighting variations. The fixed number of passes is given by the value of the CACHE PASSES COUNT option if positive. If negative, a convergence threshold is computed as: convergence threshold = 1.0 + 1.0 / CACHE PASSES COUNT. Then, the cache is refined until it converges to at least the convergence threshold value.

SHOW SAMPLES

OPTIONS: [integer: 0, 1, 2 or 4]

This option is mainly for debugging purposes as it discards any shading operation to only render the position of the selected GI samples. Its use should be reserved to expert users.

0 means show no GI samples. 1 means show GI estimator samples. 2 means show GI cache samples. 4 means show pixels where GI cache samples were used to approximate glossiness (in magenta).

CACHE TRANSPAR DRAW

OPTION: [Boolean: false, true].

If this option's value is false, then an indirect irradiance cache set on a VRL won't be rendered for transparent objects for all cameras that have the option turned off. This saves render time in configurations where transparent objects are almost not diffuse (all common glasses) and for which the global illumination contribution can be neglected. By default, this option is disabled, so that we render faster ignoring transparency rendering passes.

CACHE HEMI SAMPLING RATE

OPTIONS: [integer 1 to Infinite]

Indicates the number of samples to be taken while sampling the hemisphere. The real number of samples is the square of the option value.

This is the square root of the actual number of samples taken to estimate the global illumination at a given location during the global illumination cache computation. If a null or negative value is set, a value of 1 will be automatically assumed.

CACHE PRECISE

OPTION: [Boolean: false, true].

Enable the high precision computation mode for the global illumination cache. If enabled, small geometric details are automatically detected by the engine and better GI estimation is performed. This is good to avoid interpolation artifacts over fine geometry variations like cabinet gaps, tiles edges, window frames...

GLOSSINESS

OPTION: [double 0 to 32].

This option enables the use of the global illumination cache for the acceleration of glossiness computation. Because glossiness is a blurry effect, we can use computations of cheaper quality for rays being spread through a glossy reflection/refraction as they will finally be averaged together. Once turned on, the option lets the engine to reconstruct an approximation of the lighting reaching a point by requesting the global illumination cache instead of directly compute the illumination. This can dramatically reduce the time needed to render a scene with a lot of glossy materials.

The lesser the value, the better the glossiness quality (a value of 0 turns glossiness approximation off). If no GI cache has been computed, the option has no effect and is considered as disabled.

LIGHTING

OPTION: [Boolean: false, true].

This option enables the use of the global illumination cache for the enhancement of sampled lights rendering.

If turned on, the engine uses the global illumination cache to concentrate sampling on meaningful lights. This generally leads to an increase in lighting quality with no decrease in rendering time. However, the effect of the option is closely related to the quality of the GI cache. Hence, it performs best with default or higher GI cache settings.

If no GI cache has been computed, the option has no effect and is considered as disabled.

This option has no effect if path tracing is used to render the scene

GAMMA

OPTIONS: [integer 1 to Infinite]

Sets the gamma value for image gamma correction. Due to the non-linear response of the monitors, gamma correction may need to be applied to image prior to displaying them onto the screen.

Gamma correction is applied as follows:  output color =  input color ^ (1.0 / gamma)

WHITE COLOR BALANCE

OPTIONS: [color, as RGB/HSV]

Sets the white color to be used as reference when applying white balance.

Color balance is needed to compensate for un-natural looking of images rendered under some conditions. For example, an indoor scene by night lit only by artificial light sources may look too yellow. At the opposite, an outdoor scene may look too much blue.

A kind of auto white balance (as provided by consumer cameras) can be achieved by passing the average image color to SetWhiteReference.

If not, the input color components are clamped to the [0,1] interval.

TONE MAPPING

OPTIONS: [clamp, photographic, neutral]

CLAMP = RGBA color components are clamped to [0.0, 1.0].

PHOTOGRAPHIC = Tone mapping operator derived from photographs' best practices.

NEUTRAL = This is the neutral 'no tone mapping' operator that does not change any input color.

CURVE

OPTIONS: [curve via points]

Sets the curve to be applied to image colors.

A curve can be defined which transforms input intensity. This is a common and easy way to apply intensity corrections to a whole image. For example, an S-curve is efficient to increase image contrast by lowering low intensity values and boosting high ones.

The curve is set by passing curve samples. Each sample is made of its position along the x-axis as well as the curve value at that position. No more than 65535 samples can be provided.

The curve is built back from the samples using Lagrange polynomials for interpolation.