This material plugin is used for some advanced features of Forest, as Random Tinting or Fake Shadows.
It is mainly used on billboards, if you want to add color variation on 3D objects, we suggest to use Forest Color, that is a 2D texture map.
It works as a enveloping layer over the base material used on the object, and modifying the result of this (applying the tint, or hidding the shadow planes).
You can use any material as base (from Standard Mat. to VRayMtl), but for billboard trees we suggest to use a Standard Material (specially with Mental Ray), because some features only work with it.
Forest Material is compatible with V-Ray, Mental Ray and Scanline renderers only. For other renderers you can use native shaders for billboards.
On Multi-sub materials, always use "Forest Material" as a sub-material, in this way:
When billboard trees are used, Forest has native support of shadows using our XShadow plugin or raytraced lights. For each tree, two opacity textures are used: vertical and horizontal.
By default, XShadow searches automatically in the the material tree to find the vertical texture (Standard, Multi Sub-Object and "Forest Material" only) but this can be defined explicitly in Planes Material using this parameter. The horizontal texture must always be assigned here.
Raytraced shadows and Mental Ray need "Forest material" to work, because this plugin does the job of hiding or rendering the shadow / texture for each plane. Be sure that the material applied to the Forest object uses the "Forest Material" plugin as a base.
By default, Forest uses the Random Tint values defined in Forest->Material rollout for all tree samples used in the object, but those parameters may be overrided here for each material.
This feature is specially useful for mesh objects that use a Multi-sub material (as mat.ID 1 for trunk, mat.ID 2 for leaves), allowing to apply different tint for leaves and trunk (or disable tinting setting Min/Max values to 0).
Forest Shader (Mental Ray only)
Forest includes a custom shader that enhances the rendering of billboard trees. It fixes some problems inherent to planar trees, as the illumination or the slow transparency computing in raytracing modes. Although the shader must work in all modes, if you are experiencing some material issue or get unexpected results, you can disable it from here.
Forest Shader works only if a "Standard Material" is used as base material. This is specially important for billboard trees, for Custom Objects you can use other type of materials if you like.
The behaviour of Forest Shader is defined by some parameters of the Forest object as well. See Forest reference->Material for details.