Environmental Engineering Reference
In-Depth Information
Vegetation Model Library
Vegetation elements, especially trees, can render the landscape more realistically
than simple 2D textures. Producing high quality 3D vegetation models is a very
time-consuming and costly operation, and it is not yet planned to create such a
library for vegetation objects. As a viewer moves away from the object, we need
the model to switch from a geometric representation to a cross-polygon model, and
to a billboard (one or a combination of several two-dimensional images), such as
presented in Fig. 6.
4
.
Building a variety of realistic plant models at multiple levels of detail could be
accomplished using a package from our commercial partner (i.e. REALnat® by
Bionatics®
http://www.bionatics.com/
)
. An example is presented in Fig. 6.
5
.
Another solution is to represent less realistic plants using basic primitives such as
cone, cylinder, sphere or convex hull (Fig. 6.
5
).
At present, SLE is available only with a small number of simplified samples of
AMAPsim files (full detailed 3D tree models) and free 3D models from 3D-Diggers
Furthermore, we have planned to build a content library based on existing
vegetation textures and models. This library should eventually include some major
European species and be linked to the land cover classes. Such a library should also
offer the possibility for the user to include additional textures according to land-use
and vegetation not accounted for in the first versions.
Fig. 6.4
Two level of detail plant models from REALNat® by Bionatics®. A high level of detail
is necessary when visualizing the object from a nearby position (
left
) and a lower level of detail
when visualizing it from afar (
right
)
