Applies a random color tint to the items. There are two possible modes of operation, tint by gradient and tint by map.

In this section:



Color Tint

Get Color from Gradient

You may define a Color Range by clicking in the color boxes, and the Random Strengh range determine the magnitude of tint applied, from 0 to 100%. Use Min=0 and Max=0 to disable the effect.

Get Color from Map

Forest uses a custom map as tinting source. With "Random Values", a random pixel from the map is taken for each tree, and "As Texture" applies it as a standard Max texture.

By default, Forest uses the parameters defined in the Distribution Map rollout (X/Y, offset, rotation...) for scaling, but it's also possible to get the mapping coordinates from the surface, if there any assigned in the Surfacerollout, and a value greater than zero is assigned to "Map Channel".

Color Tint requires Forest Material or Forest Color to work. Be sure that the materials used in the Forest object (assigned in the Geometry rollout or applied directly to the object) use one of these plugins. "Forest Material" is a custom Material included with Forest Pack, and "Forest Color" is a 2D texture map. Without them, Color Tint won't work.

It is possible to customize the tinting options for each material using the "Override" option. See Forest Material and Forest Color reference for details.


Forest Shader

Forest includes a custom shader that enhances the rendering of billboards. Currently, it's only available for Mental Ray. The following parameters adjust the behaviour of this shader. As all options on this rollout, require the use of materials based on "Forest Material" plugin.

Trace Depth

Maximum raytrace depth used to compute the opacity maps, default value is 3.

Opacity Level

Defines the minimum level of opacity of the mask textures used by Forest Material. As instance, a value of 0.8 considers all pixels darker than RGB=204,204,204 (255*0.8 = 204) as opaque. It's used to optimize the computation of opacity maps.

These parameters are used to speed up the rendering, but in some situations using lower values would create image artifacts. To disable them use Trace Depth=99, Opacity Level=1.0.

Self-illum factor

This parameter works as a multiplier of the self-illumination value, for all materials used by the Forest object. Use it to adjust the Self-illum effect, without having to modify each material individually.

Irradiance Color

Defines the effect of global illumination on the Forest object when "Final Gathering" is enabled (Mental Ray renderer options).

To get the best results with these parameters, we suggest this configuration for Mental Ray scenes:

With Final Gathering enabled:

  • Forest Self-illum factor: 20% to 100%
  • Material Self-illum: 50%. Create all your new materials with this value, you won't need to modify it... use SI factor instead. All materials of the Forest libraries have 50% by default as well.
  • Irradiance Color: default
  • Use SI Factor + Irradiance to get the desired global illumination over the trees.

Final Gathering disabled:

  • Forest Self-illum factor: 20% to 100%
  • Material Self-illum: 50%.
  • Irradiance Color: not used

Optimize Materials

This tool helps you to convert and optimize the materials used by Forest, selecting automatically the best settings for each renderer. It includes the following features:

  • Convert Standard Materials to VRay (VRayMtl) / Mental Ray ( Arch & Design).
  • Apply Forest Color to the Diffuse maps.
    • You can optionally control the RGB level
    • If there are materials you do not wish to use a Forest colour map include their names here. For example it is often the case that you only want to randomise leaf colours not the trunk and branches. Separate material names with spaces.
  • Apply Forest Material (billboards only).
  • Disable filtering for Opacity Maps (recommended for leaves created using alphas).
  • Modify Custom Objects material. When this is on materials applied to custom objects as well as billboards will be optimised
  • Apply Forest Edge. Add Forest Edge maps to opacity slots to enable the object to function with Areas > Edge mode. 


To demonstrate the benefits of the Material optimizer, we have created this free Alpine Lake scene which uses XFrogPlants. The render time is over seven times faster over using standard materials.