Modeling the Details - Blender Master Class: A Hands-on Guide to Modeling, Sculpting, Materials, and Rendering - page 60

In order for IvyGen to generate vines, it
needs a single mesh object for them to grow
over, so we need to create a new mesh that
includes all of the geometry we want to grow
vines over. To do so, select all of the objects
you want the ivy to cover, duplicate them
( shift -D), apply any modifiers (using the
Convert to Mesh operator in Object mode—
flat -C), and merge them into one object
( ctrl -J). The result should be one object. If
your scene has a high poly count, you might
want to skip applying modifiers that increase
the poly count a lot in order to give you a
lower-poly mesh to grow ivy over; unfortu-
nately, this may come at the cost of some
accuracy in how it will grow.
Later, once you've finished growing your
ivy, delete this duplicate or move it to another
layer so that it doesn't get in your way ( M ).
Next, place the 3D cursor where you want
the ivy to start and activate IvyGen with the
Add Curve menu ( shift -A 4 Add Curve 4 Add
Ivy To Mesh ). The IvyGen allows you to tweak
numerous parameters to determine how the
ivy looks, the most important of which are
the Max Ivy Length option, which determines
how far the ivy spreads, and the Ivy Size and
Leaf Size options, which determine the thick-
ness of the vines and the size of the leaves.
The leaf probability option determines the
leaf density. Other options, like Float Length
and Adhesion Length, determine how far the
vines can reach out from the wall and how
they are affected by gravity.
Keep tweaking IvyGen's settings and
pressing Update Ivy to regenerate your ivy
with any new settings until you're happy with
the look of your foliage. Keep in mind that the
higher you set the Max Ivy Length, the longer
the ivy will take to generate. Also, if you want
to cover a large area, it's easier to run IvyGen
repeatedly using different starting locations
in order to create multiple ivy meshes. For
example, in the Jungle Temple scene, I hid the
starting locations in the corners of the scene
in a couple of different starting locations and
let my ivy grow out from there. You can see
the final results in Figure 5-21.
IvyGen also creates automatic UV coordi-
nates for the leaves and vines it generates, as

Figure 5-20: Adding puddles to the scene by first creating depres-
sions in the main ground plane mesh and then adding a second flat
plane to intersect with it

Figure 5-21: The final modeled Jungle Temple scene