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sky_base

A sky_base material is used for the sky objects.

States

In the States tab you can set rendering passes and available options. Enabling some of the states activates additional textures and parameters in the Textures and Parameters tabs respectively.

The states divide into 2 groups: Passes and Options.

Possible values for all the other passes:

GUI name XML name Description
None none Material is not rendered during the pass.
Default default Material is rendered during the pass.

Possible values for a Background option:

GUI name XML name Description
None disabled A background texture is not used.
One texture single One background texture is used.
Two textures double Two background textures are used.

All the other options can be either enabled or disabled by ticking the respective boxes.

The states available for this kind of materials are listed below.

Passes

Passes specify during which rendering pass the material should be rendered. They are modified in the Passes field of the States tab.

GUI name XML name Description
Ambient ambient Ambient rendering pass. Specifies, how the material should be rendered during the Ambient light pass for the opaque objects. The actual opacity or transparency of the material depends solely on the set blending options.
Light world light_world World lights rendering pass. Specifies, if the material should be rendered illuminated by the World light sources during the light and shadows rendering passes.

Options

The following options are set in the Options field of the States tab.

GUI name XML name Description
Background background Enables a cube map texturing of the sky sphere. This option allows to use static sky images, for example, to create a night sky with stars.
Clouds clouds Specifies if the procedural clouds will be rendered.
Soft interactionvolume Provides a proper interaction of volumetric clouds with other objects (required if Up sample box is checked). It lessens the clouds color depending on their position relative to the object:
  • If the depth value specifies, that the clouds are in front or behind the object, they are rendered as usual
  • If the depth value between the cloud and the object is small, the color is smoothly interpolated
The depth value can be set using Interaction parameter. This option allows to avoid moire patterns on the objects.

Textures

Clouds Textures

The following textures create textured sky sphere clouds and are modified in the Clouds field of the Textures tab.

GUI name XML name Description Channels
Mask 0mask_0Mask for the 1st upper cloud layer.RGBA.
Mask 1mask_1Mask for the 2nd lower cloud layer.RGBA.
Clouds 01clouds_01Noise texture for the 1st upper cloud layer.RGBA.
Clouds 23 clouds_23 Noise texture for the 2nd lower cloud layer. RGBA.

The color of the textured sky sphere is calculated in three steps:

  1. The upper layer of the clouds, Clouds 01, is computed:
    1. For the first layer, two texture transformations (Clouds 0 and Clouds 1) are summed.
    2. Mask 0 is multiplied by the Threshold 01, modulating the strength of masking.
    3. The mask is subtracted from the textures transformation sum.
    4. The color intensity of the resulting Clouds 01 layer is computed by multiplying it by the Clouds 01parameter value.
  2. The lower layer of the clouds, Clouds 23, is computed in the same way:
    1. For the second layer, two texture transformations (Clouds 2 and Clouds 3) are summed.
    2. Mask 1is multiplied by the Threshold 23, modulating the strength of masking.
    3. The mask is subtracted from the textures transformation sum.
    4. The color intensity of the resulting Clouds 23 layer is computed by multiplying it by the Clouds 23 parameter value.
  3. The rendered clouds are adjusted by the Sphere value that controls the influence of atmospheric scattering on the clouds.

Additional Textures

These textures are present depending on the Background option selected.

GUI name XML name Description Channels
Background 0background_0A cube map for texturing the sky sphere with a static textureRGBA.
Background 1background_1A second cube map for texturing the sky sphere with a static textureRGBA.

Parameters

In the Parameters tab you can set or modify base and additional parameters.

Parameters of different types are set in different ways:

  • expression - vector values can be set either in the field near the parameter or in the dialog window opened when double clicking this field
  • slider - the value can be set either by smoothly moving the slider of the scroll box or manually in the box near the parameter (if required, the value bigger than maximum one for the slider can be set)
  • color - the color can be chosen in the dialog window, activated after double clicking the color field

The parameters available for this kind of materials are listed below.

Transform Parameters

Textures transformation parameters are modified in the Transform field of the Parameters tab.

GUI name XML name Type Description
Spheresphere_transformexpression Transformation of the sky sphere:
  • The first two components scale the sphere by X and Y, respectively. They affect the circle of a horizon
  • The third component scales the sphere by Z, making the sky look higher or lower
  • The fourth component offsets the sphere vertically. Positive values move the sphere down, negative values move it up. This can be used to remove cloud artifacts near the horizon
Volumevolume_transformexpression Transformation of the volumetric clouds mask.
Noisenoise_transformexpression Transformation of the volumetric noise texture.
Mask 0mask_0_transformexpression Transformation of the mask texture mask_0.
Mask 1mask_1_transformexpression Transformation of the mask texture mask_1.
Clouds 0clouds_0_transformexpression First transformation of the cloud texture clouds_01.
Clouds 1clouds_1_transformexpression Second transformation of the cloud texture clouds_01.
Clouds 2clouds_2_transformexpression First transformation of the cloud texture clouds_23.
Clouds 3clouds_3_transformexpression Second transformation of the cloud texture clouds_23.

Volume Parameters

Volume parameters control the appearance of volumetric clouds. They are modified in the Transform field of the Parameters tab.

GUI name XML name Type Description
Color 0volume_color_0colorVolume color of the volumetric clouds
Color 1volume_color_1colorShadowed volume color of the volumetric clouds
Multiplierslidervolume_01_scale Color multiplier for the volumetric clouds:
  • Decreasing the value results in dark and unsaturated color
  • Increasing the value results in light and very saturated color
Scatteringslidervolume_scattering Coefficient controlling the influence of atmospheric scattering on the volumetric clouds:
  • Decreasing the value results in clouds disappearing close to the camera
  • Increasing the value results in clouds spread far towards the horizon
Turbulenceslidervolume_turbulenceThe size of noise applied to the volumetric clouds:
  • 0.1 is a neutral value
  • Higher values result in grainy, whipped and rough clouds
  • Lower values result in soft and solid clouds

Clouds Parameters

Clouds parameters control the appearance of textured sphere clouds. They are modified in the Clouds field of the Parameters tab.

GUI name XML name Type Description
Clouds 01clouds_01_scalesliderColor intensity of the first cloud layer:
  • Decreasing the value results in cloud color fading
  • Increasing the value results in cloud color intensification
Clouds 23clouds_23_scalesliderColor intensity of the second cloud layer:
  • Decreasing the value results in cloud color fading
  • Increasing the value results in cloud color intensification
Threshold 01clouds_01_thresholdslider Coefficient modulating the strength of masking of the first mask:
  • Decreasing the value determines a weakened attenuation by the mask and abundant clouds
  • Increasing the value determines an intensive attenuation by the mask and sparse clouds
Threshold 23clouds_23_thresholdslider Coefficient modulating the strength of masking of the second mask:
  • Decreasing the value determines a weakened attenuation by the mask and abundant clouds
  • Increasing the value determines an intensive attenuation by the mask and sparse clouds

Sphere Parameters

Sphere parameters are modified in the Sphere field of the Parameters tab. Backgroud 0 and Background 1 parameters are present only if Background option is set to One Texture or Two Textures mode respectively.

GUI name XML name Type Description
Scatteringsphere_scatteringsliderCoefficient controlling the influence of atmospheric scattering on the sky sphere clouds:
  • Decreasing the value equals a prominent distant-depending attenuation due to the scattering effect and a soft horizon line
  • Increasing the value equals an insignificant distant-depending attenuation and a hard horizon line
Background 0background_0_scalesliderColor multiplier for the first background texture:
  • Decreasing the value results in dark and unsaturated color
  • Increasing the value results in light and very saturated color
Background 1background_1_scalesliderColor multiplier for the second background texture.

Soft Interaction Parameters

Interaction parameter is present only if Soft interaction option is enabled and is modified in the Soft interaction field of the Parameters tab.

GUI name XML name Type Description
Interactionvolume_scaleslider Depth factor that controls the volumetric clouds dispersal depending on their position relative to the object (see Volumetric interaction description):
  • The higher the value, the closer objects are veiled by the volumetric clouds, because the close positioned clouds are rendered in full color
  • The lower the value, the further positioned objects are seen clearly even though being inside of volumetric clouds. This happens because nearby clouds are rendered transparent
  • By the value of 0, the depth value is considered to be infinity, and thus there will be no volumetric clouds. The whole cloud volume will be rendered transparent

Shadow Parameters

Shadow parameter controls the appearance of shadows from clouds and is modified in the Shadow field of the Parameters tab.

GUI name XML name Type Description
Multipliershadow_scalesliderDarkness of shadows cast from clouds to the surface beneath:
  • Decreasing the value results provides darker shadows
  • Increasing the value results provides lighter shadows
Last update: 2017-07-03