Surface
In the
most of forest scenes, we will have not planar surfaces to place
the trees, instead it we will have hills, mountains, etc. With
this panel we can choose the surface to placing trees over it.
Pick / Clear / Update
With 'Pick' button we must choose the object scene which represents
the terrain. The trees of Forest always are created in XY plane,
so the terrain must be placed over this position and must be
a simple mesh (we cannot use groups, etc.)
With 'Clear' button, terrain selection is cleared and all
trees will back to XY plane.
If we modify the terrain, the objects will not adjusted automatically
over the new surface, we must use the 'Update' button to inform
to Forest the new situation. We know this may be a limitation
for some scenes with animation of terrain, but it's implemented
this way because Forest builds an internal table with the characteristics
of terrain to optimize the speed when placing trees. So, it's
possible to rebuild the trees in realtime with or without surface
defined (over 50.000 trees/sec. in a Pentium II-350).
Anyway, this table is common for all Forest objects, so when
we have using the same surface for several Forest objects only
is necessary to use the 'Update' button in one of them. All trees
are placed automatically.
Altitude Range
These parameters define the limits to place trees by height
levels. When the 'Limited' checkbos is enable, only will be created
trees in the range specified by Top and Bottom.
Slope Angle Range (Rango de
Inclinación)
Limits the creation of trees over a range of slope terrain.
0 degrees is equal to a horizontal surface, and 90 degrees is
a totally vertical surface.
Note: The plugin first calculates all trees over the area
and following, it discards which all not inside the altitude
and slope range. So, the time to build the trees may be almost
equal when altitude/slope ranges are defined or when all trees
are built. It's importante to limit before very well the build
zone with the area splines and distribution map. |