(comes from
part 1)
Until now, the tutorial may be completed with the freeware
version of Forest (Forest Lite). But, from this point, you will
need Forest Pro to use and learn the advanced options of the
plugin. Anyway, if you have not it, we recommend to read this
section so you may know the capabilities of the software.
Irregular Terrains
Now we have our house surrounded by trees, we will like to
fill also the far hills with vegetation.
We set the top viewport to work more easily and unhide the
'trees 2 spline' object. This is a spline which surrounds the
hills. We make a new Forest object using these values:
- Size of trees: 3m for width and 6m higher. One Plane for
geometry
- Distribution map: 'Dense', with a size of 190m x 190m. Offeset
to 0,0 and the other values by default.
- We use the 'trees 2 spline' as inclusion spline area
- Set the 'cam1' camera in camera rollout with 'Trees looking
camera' and 'Limit to visibility' enabled
- Scale transformation: 80% to 150%. Enable 'lock aspect ratio'
checkbox
Finally, we assign the material 'trees' to the object and
set the 'cam1' view as main window.
We are going to say to the plugin it must adapt the trees
over the hills. Open the Surface rollout:
First of all, click
in the 'Pick' button and select the 'terrain' object (same way
as used for camera an areas).
Two important details:
If we modify the terrain, the trees don't place over the new
surface automatically. We must use the 'Update' button to inform
to the plugin that the surface have changed. Forest maintains
a internal table with the characteristics of the surface to optimize
the build speed and it must be recalculated with the update button.
Without this method, Forest will not be able to build the trees
in realtime.
If exists several Forest objects which use the same surface,
only is necessary to use the update button in one of them. The
internal table is common for all.
In this panel, we can also limit the creation of trees at
differents heights and slopes of surface.
With 'Altitude Range' we can define the limits (in scene's
unit) for altitude so the trees only will be created inside this
range. It's very useful for clean the snowed peaks and specify
different vegetations at levels of terrain.
In a similar way, the 'Slope Angle Range' defines the minimum
and maximum angles for allow build trees. 0 degrees is a horizontal
terrain and 90 degrees is a totally vertical surface.
By example, we enable the 'Limited' checkbox of this panel
and lower the maximum slope angle to 35 degrees. While we change
it, we look as the trees are been cleaned from the most sloped
areas. Leave at 35 degrees to follow the tutorial.
Render now to get this image:
Differents species of trees
Now our scene have a very good aspect , but it need some details
yet. Per example, we will like that the trees will have different
textures to give more diversity to the scene. We open the Material
rollout:
With this rollout
it's possible to apply random materials automatically. To achieve
this, we must use compound materials.
Change the radio button from Fixed to Random. Don't change
the numeric values.
Now, the trees of hills change his texture from two different
randomly. Evidently, the material assigned to the Forest object
is compound by two sub-materials (open the material's editor
to see it).
Shrubs and Flowers
Already we have seen all the rollouts of Forest, now we are
going to practice a bit adding more vegetation to the scene.
We are going to create some shrubs and flowers.
Unhide the 'shrubs spline' and create a Forest object with
the following values:
- Width: 1m, Height: 0,376m. Geometry: One Plane
- Area spline: 'shrubs spline'
- Distribution map: 'Groups 1' with 38m x 38m size
- Use the 'cam1' camera with 'Trees looking camera' and 'Limit
to visibility' enabled.
- Scale transformation between 100% and 120% with lock aspect
ratio enabled
- Random material 1 to 3
- Apply the 'shrubs' material
A render must show this scene:
Adding Grass
Almost we have finished. We are going to add some grass besides
the road and also practice other advanced features of the plugin:
Unhide all the objects of scene and create a Forest Object
with these values:
- Width: 0,3m, Height: 0,5m. Geometry 'Custom Mesh' with the
'grass sample' object.
- Area: Use the 'grass spline' object.
- In the Display rollout, set the 'Simplification Level' for
viewport to 2. This is a complex object and we like to speed
up the redrawing a bit.
- Distribution Map: Choose a custom bitmap clicking in the
button under 'File Name' an use the 'grass_mask.jpg' file (it
may be found in the same directory of tutorial texture maps).
Lower the 'Minimum Tree Separation' to 10%. Deactivate the 'lock
aspect ratio' checkbox and set a size of 30m x 75m. Offset must
be -2,7 and 2,7 for X and Y. Threshold: 45%
- Use the 'cam2' camera with 'Trees looking camera' and 'Limit
to visibility' checked.
- Transform: Apply random translation of 25% for X and Y. Scale
transform from 80% to 120% with lock aspect ratio checked.
- Apply the 'grass' material
We are going to analyze a bit the last work:
We have creared a Forest Object but with a custom mesh geometry.
In this case, a leaf of grass (the 'grass sample' object). Also
we may have used a planar object with a texture, but in this
scene the result is best with this method. Also, is important
to know that, sometimes, the render time may be more fast with
mesh objects than using opacity textures (when there are a lot
of opacity objects overlapped). On the other hand, the custom
meshes use more memory. Depends of the scene and the memory installed
in our computer we will like to use one or other method. Anyway,
alway we must use meshes with the minimum required number of
faces (this grass leaf has 39 faces).
Also, we have used a custom distribution bitmap to place the
grass following the road (a very specific distribution). The
values for size and offset are calculated testing until we got
the grass placed over the desired place.
Also we have used a different camera (it's placed lower than
'cam1') to obtain a better artistic result and to appreciate
better the grass efect. Only rest use the cam2 viewport a make
the final render:
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