Creating Organic Materials - Blender 2.6 Cycles: Materials and Textures - page 242

Creating tree shaders - the bark
There are several different ways to build trees in a 3D package: starting from the
simpler low poly objects such as the billboards used in video games (simple planes
mapped with tree images on a transparent background) to slightly complex objects
where a trunk mesh is attached to a foliage mass made of little alpha textured planes,
each one representing a leaf or even a twig, to more complex and heavy meshes
where every little branch and leaf is actually modeled.
For this two-parts tree shader recipe, we will use a model coming from the many en-
vironment assets of the CG short film Big Buck Bunny , the second Open Movie pro-
duced by the Blender Foundation. All the movie assets are free to be downloaded,
distributed, and reused, even for commercial projects, because they are licensed un-
der the Creative Commons Attribution 3.0 ( http://creativecommons.org/licenses/by/
3.0/ ) .
The general shape of the tree and of the leaves as well is pretty "toyish". This is be-
cause they are the elements that have been drawn to match the toon style of the furry
characters, but actually, it's perfectly suited for our demonstration purposes.
The tree model is made up of several parts: on the first layer there are the tree_trunk ,
tree_branch , and tree_branches meshes and on the second layer the leaves, made
up of a single leaf object dupliverted on the tiny faces of the leaves_dupli object
(that is the leaf_tobeswitched object is parented to the leaves_dupli object and
then, in the Object window, under the Duplication tab, the Faces duplication meth-
od has been selected, the Scale option checked and the Inherit Scale value set
to 1110.000 . This way the leaf_tobeswitched object is instanced on the many
leaves_dupli faces according to their location, rotation, and scale).