Kray plugins

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Kray Master Plugins

Master plugins can be accessed by going to Utilities tab > Master plugins and from the top listbox Add layout or scene master choosing the appropriate Kray plugin.

Kray PhySky plugin


This plugin create physicaly correct sun and sky for easy lighting of your scene. The map allows you to select the location on earth by clicking on it. You can also select from the predefined list of cities. The position of sun will be automatically adjusted based on location and time of day/year.

Most of the settings should be self explanatory.

Nort Offset

Default north orientation is +Z axis. If you want to rotate position of North you can do so here.


This setting controls the color of the sky and sun. Lower values produce more clear Blue sky while higher produce more foggy, yellow sky and sun.


Controls the brightness of the sky and sun. Increasing this value will make your scene brighter.

Ignore Light

You can select a light from the scene that will be ignored by Kray. This is handy for example if you have a Sun light in a scene which you use for LightWave or Fprime rendering but you want to ignore it in Kray.


Volumetric effect adds a haze like effect to the scene. This can be applied to backdrop only or to full scene. Affect Backdrop: will apply volumetric effect only to backdrop. Affect Shadows: will apply volumetric effect to backdrop and shadows. Affect All: will apply volumetric effect to backdrop, shadows and geometry. This may increase rendering time.

Ignore LightWave backdrop

You can check this box if you want to ignore LightWave backdrop completely.

Use Physical Sun

When this option is off PhySky will only render light coming from sky. You need to turn this option on to get light and shadows from Sun.

Sun Intensity

This setting controls Sun intensity separately from the exposure control above. The exposure control controls the overall brightness of the sky while Sun Intensity controls only the sun.

Sun Softness

This setting controls softness of sun shadow. Increasing this number will make Sun shadow softer.

Sun Power Mult.

Sun Power Mult. Example

This setting controls power of indirect light coming fron physical sun. Increasing this number will make sun's bounced light brighter.

Kray Tonemap Blending plugin


This plugin allows you to mix two tone mappers together.

Note: Make sure you turn tonemapping in Kray General tab to "Linear". Otherwise this plugin will be adding tone mapper on top of the one from the general tab.

1st / 2nd Tonemap

Pick the first of the two tonemappers you want to mix.

HSV : This parameter tells Kray to tonemap image by keeping saturation of colors close to original. Parameter : Adjust value of the tonemapper. Higher values produce less contrast while low more. Exposure : If you want to increase or decrease the exposure of your image enter appropriate value here.


With Blending you control how much of each tonemapper the final image contains. Value of 100% means that only 1st tonemapper will be used while 0% means only 2nd tonemapper will be used. Values in between mix 1st tonemapper with the second.

Quick Linear Workflow plugin


If you ever played with gamma values in Kray GUI you have probably noticed that increasing gamma can bring to washed out looks and changing color tones in textures. This plugin will help you get better and more accurate colors in your renders. The plugin tonemaps the incoming colors and textures so that they are calculated properly within Kray. Parameters:

Input Tone Map

with this settings you choose the tonemap of your input images and colors. Usualy this setting should be kept at Gamma.


This is the value of your input tonemap. Usually images on computers have gamma value of 2.2 so this is what you enter here.


If you want to increase or decrease the exposure of your input colors/textures enter appropriate value here


This parameter tells Kray that input images are tonemapped in HSV mode.

Affect backdrop

will use quick LWF settings for backdrop

Affect textures

will use quick LWF settings for textures

Affect lights

will use quick LWF settings for light colors

Kray Override - Surface Override GUI


This is a master plugin that will help you control surface override settings.

Enable Override

Will let you quickly enable/disable override in Kray.

Override with color

Will render the object in a specified color while keeping all other channels intact (diffuse, reflection, transparency, ...).

Opaque to light

Will prevent light from passing through transparent surfaces.

Pure color

Will render surfaces in pure matte color (no textures, no shading).

Pure diffuse

Will render surfaces as a pure diffuse without any textures, colors, reflections, etc.

Disable ...

Disable Textures will turn off all textures. Disable Refl/Refr blurring will turn off all reflection and refraction blurring. Disable Luminosity will turn off all luminosity. Disable reflections will not render any reflections. Disable transparency will render transparent surfaces as opaque. Disable translucency will not render translucency.


This option will render out polygon edges in wireframe overlay. You can control the thickness, the smoothing and color of the wireframe.

Here's an example of different override options:


Kray Buffers


Kray Buffers GUI will lets you choose which buffers you want to output from Kray. Kray will create a separate file with a buffer name in the filename.

The settings are pretty self explanatory so we will not get in depth about each buffer here.

Z buffer

Z buffer mode

  • linear: linear gradient from black to white
  • inverse: inverted linear gradient from white to black
  • log: logarithmic gradient from black to white

Clip: distance of front and back clip plane. Values above and this will be clipped. If you want to turn clipping of enter -1 for Back. Value: here you can define value of front and back pixels. The number is float so you can use it with HDR Z buffer.

The buffers can be comped together with this formula:

final image=tone_mapping_operator((caus+dire+indi)*txtr+othr+lumi+refl+refr)

Kray Custom Object plugins

Custom object plugins can be added to object by going to object properties and on the Geometry tab clicking on Add custom object' list.

Kray Instances


Kray instances plugin allows you to easily place thousands of instances into your scene. The plugin allows random scale and rotation and some other useful options. It's a Custom Object plugin that should be applied to the object (template) that defines position of your instances. The template can be either polygon mesh, 1 point polygons or pure points (no polys). Pivot point of the object will be used as the center of the instance so make sure it is properly positioned otherwise you may get unpredictable results.

Object to clone

Choose object that will be instanced

Object to Follow

Here you can choose object that instances will “follow”. Instances will use it’s rotation and scale parameters.


Here you define random rotation settings.

Use normals

Turning this ON will align instances to template mesh normals (only works on polygons!).


Here you define random scaling settings.

Lock XYZ Size

Turning this ON will lock X, Y, Z scale parameters so object will be resized equally on all axis.

Use Color

Turning this ON will use color from the template object and color filter the instances.

Use custom object

You can use special object to place your instances. The default object is triangle 1mx1mx1m in size with a 2 point polyline defining it’s axis. This object defines position, orientation and scale of the instances. Note: you can still apply random rotation/scale values on top.

Example scene

Download an example scene here: Kray Instancing example scene

Kray Surface Shaders

Surface shaders can be applied to surfaces by opening Surface editor and on the Shaders tab clicking on Add shader list.

Kray Surface Options

The KraySurfaceOptions Shader can be used to change various Kray settings for each surface.



Turns the visibility (from everything, camera, rays, reflection etc) of the surface on/off.

Control diffuse model

Enables you to change the GI model for this surface only. The available models are all that are normally available to Kray : Raytrace, Photon Filtered, Photon Filtered+Raytrace Direct, Photon Mapping, Path Tracing.

Cache Irradiance

(only available with Photon Mapping and Path Tracing) Allows you to turn on or off Irradiance Caching for this surface.


Allows you to turn on or off caustics for this surface.

Reflect Caustic photons

In a scene that has Caustics on, unchecking this will disable the production of reflection caustic photons from this surface. If the scene has Caustics off this setting will do nothing.

Control FG rays

Allows you to use different number of rays for this surface, so you can use less rays for areas

Control Reflection Blur

Allows you to use different number of reflection rays per surface, so you can for example use more rays for the floor surface and less for the rest of the scene.

Trace direct

Same as trace direct light reflection in the quality tab.

Accurate reflection

Allows you to override the Blurring accuracy limit setting in Kray rendering options and use the FG solution instead of photon filtered for reflection of this surface.

Force indirect luminosity

Allows you to make a luminous polygon emit light indirectly regardless of the settings in the Quality tab of the Kray rendering options.

Kray Indirect Rays



This can be used to control color bleeding. The percentage represents how much the light that bounces of the surface will be desaturated.



Multiply can increase or decrease the amount of light that bounces off the surface.


Limit Dynamic Range

Limits the dynamic range of the indirect rays that leave the surface. Can be used on luminous geometry that emit light indirectly. The emitted light is clamped to limit dynamic range value eliminating over bright values which effectively reduces possible splotches (but also the power of the emitted light gets reduced as well), while the surface itself appears to be very bright. This is an unrealistic function but it can be a useful tool too when you want to improve your result without caring too much for realism.

Kray Light Portal


See also Using Lightportals tutorial.

The KrayLightPortal can be used to make some surfaces act as Light Portals. Light Portals are special surfaces that will guide photons into places where you need them. This helps you get better photon distribution in places where you need it. Remember that the Light portal surface normal should be facing towards the light source you want it to attract photons from. A tutorial on how to use this shader can be found here: Using Lightportals.

This shader is useful only in Photonmap mode since Lightmap already distributes photons in based on camera view.


This Drop down list enables you to link this light portal to a specific light. If you want to link multiple lights to a specific light portal you can add the KrayLightPortal shader multiple times on the same surfaces.

Enable Photons Portal

Ticking this will make this surface act as a Light portal

Importance: This percentage amount to the percentage of photons that will be aimed at this surface.

All lightportals importance: This shows you the added importance of all light portals. If the sum of all light portals exceeds 100% the percentage of the other light portals will be reduced so that the sum is 100% once you exit the light portals panel.

Enable Caustics Portal

Importance: This percentage amount to the percentage of caustic photons that will be aimed at this surface.

All lightportals importance: This shows you the added importance of all light portals. If the sum of all light portals exceeds 100% the percentage of the other light portals will be reduced so that the sum is 100% once you exit the light portals panel.

KrayPhotonMultiplier Surface Shader


With this shader you can control the amount and intensity(power) of photons leaving the surface. This is similar to power multiplier setting in the Kray GUI - Photons tab but it work on per surface basis.

Luminosity number multiplier

You can increase the number of photons emitted from Luminous surface by increasing this number.

Luminosity power multiplier

You can increase the power (intensity) of the photons emitted from Luminous surface by increasing this number.

Diffuse number multiplier

You can increase the number of the photons bouncing from diffuse surface by increasing this number.

Diffuse power multiplier

You can increase the power (intensity) of the photons bouncing from diffuse surface by increasing this number. This can be helpful for example in a room with dark floor where bounced photons would be few. Increasing this setting will make the room lighter as if the floor was brighter.

The Kray motion modifier

The motion modifier plugins can be added to the object/light by pressing 'm' key or going to Window > Motion options. In the bottom of IK and modifiers tab the Add modifier list contains the list of plugins available.


Photonmultiplier modifier.png

KrayPhotonMultiplier modifier controls how much photons a light source emits. You can apply this modifier to a Light or an object containing luminous polygons.

You should assign this shader to a light source that is not emitting enough photons or if you want the power of light to be stronger.

Photon Number multiplier

This setting will increase the number of photons the light emits.

Photon Power multiplier

This setting will increase the power of the photons the light emits. Note that the intensity of the direct light will not be stronger. Only bounced light will be brighter.

You must experiment to find the right value but that's usually quite easy: just render in Photon estimate - Global unfiltered or Precomputed mode and find the right balance.

Here's an example of a render without using PhotonNumberMultiplier:

And here's an example of a render with PhotonNumberMultiplier 100000.0:

Modeler Plugins


When using direct luminosity model, Kray will only recognize 1 light per luminous surface/object. But when you assign different part names then Kray will treat each part as a separate light source.

This plugin automatically assigns part names to selected polygons. Each group of polygons that is connected will get one part name.

KrayAutoParts.p is available as a separate download from the Kray website.