3.2 The forest borders
The forest in TerraScene looks a little bit geometrical. Well focus on the borders and
try to give them a more natural look. The places where some forest and urban areas meet needs
some adjustment too; it looks better if we manage some smooth transition.
Remember that we work on the shadow map - we dont draw the modifications directly to
the texture map. If you want, you can do it however; I chose this method to limit the number
of images simultaneously opened. The only way to modify the textures is to lighten or darken
some parts of the shadow map which will later lighten/darken the textures themselves, after
the final merging. Keep this in mind when reading the following chapters. If some operation
seems unclear to you, look at the chapter 3.5 of this document to see the effect it will have
once the shadow and the texture layers will be merged.
Open the selection map and select
every color which maps the forest zones (be careful : not the clearings). Use the magic wand
or SELECTION > COLOR RANGE.
NOTE : I added a dark mask to the picture to highlight the selected zones.
- Save this selection as the Forest channel inside a new document. You have now
a document named Untiltled-1, which will be a container for all the
work channels to be created.
Select all kind of urban areas.
SELECT > MODIFY > EXPAND the selection to give some more room to buildings.
- Save selection as a new channel (ExpandedUrban) to the document you created
before (usually Untitled-1).
Transition with urban areas
Select the new document; take a look
at the channels you just created.
Now lets go for some calculation.
IMAGE > CALCULATIONS
Ok, do you remember the explanations before?
- Add the reverse of ExpandedUrban to Forest channel. Choose New
channel as a result.
- Rename the new channel as Forest2. The borders of the urban zones have been
removed.
Jagged borders
Select the channel Forest2.
Click LOAD CHANNEL AS SELECTION icon on the channels palette.
- Expand the selection a bit. The borders of the selection will not follow the roads anymore.
It will preserve them from being too jagged.
Contract the selection more than
you expanded.
Set foreground color to white
EDIT > STROKE the outside of the selection. The edge is erased.
SELECT > BORDER
FILTER > DISTORT > DISPLACE
Try the DMRandomLarge displacement map I gave before, or create your own. Here it
is set to 10%.
Add some contrast until the border
is sharp.
(Optional) Select the borders
again and FILTER > DISTORT > DISPLACE with a smaller and less contrasted displacement
map, this time doing the roads too.
Some cleaning : APPLY IMAGE, Add
Forest channel to erase the pixels which were displaced past the limit of the original
forest area.
The new forest is entirely included inside the limits of the old one.
Apply the changes
Now we want to apply this new shape, keeping in mind that we can only modify the final picture
through the shadow map.
Well use a little trick : the forest is generally darker than other textures. We have
to clip the Forest2 shape from Forest channels : the remaining
pixels are those that must change their look. Well just lighten those pixels and they
will loose the forest aspect.
Open the ProjectShadow.tga
document. Convert it to grayscale.
- IMAGE > CALCULATIONS : add Forest2 to inverted Forest channel, this time, choose Result
> Selection.
Adjust BRIGHTNESS CONTRAST
for selection.
Contrast must be high, and brightness slider must bring most parts to white. Be careful to keep
the relief shadows dark enough. Thats it! (Also see Part 5 : Advanced)
NOTE : We have now virtually adjusted the forest shape, but well not see the result before
the final state, when the shadow and texture layers will be merged.
3.3 The forest shadow
This adjustment will greatly improve the forests look with the illusion of relief. We
will add some stretched shadows along the forest edge, and for this well use the Displace
filter again. To achieve this effect, many ways are possible, feel free to experiment other
techniques than displacement maps. If you want to do only a limited number of steps to improve
TerraScenery, this chapter and the next one will achieve the best effects.
NOTE : Each time we use a displace filter to create some shadows, LOAD THE CHANNEL AS A SELECTION,
and then INVERT this selection. Or select the white area with the magic wand. Only then, apply
the filter. In case of successive displace filters on the same channel, no need to reload the
selection each time.
Draw the shadows
Duplicate the channel Forest2. Rename the new one ForestShadow. This
will be the work layer.
LOAD CHANNEL as selection and
invert selection.
In this way, the black area wont be messed when applying the filter. The Displace filter
uses the pixels at the edge of the selection, and the black edge pixels will be stretched
like tree shadows.
FILTERS > DISTORT > DISPLACE.
You may use here the small displacement map given at the beginning of this document. Do only
small displacements each time. It avoids jagged shadows near the very small areas. The parameters
depend on the position you gave to the sun in the shadow renderings options.
IMPORTANT NOTE : The tile option must be selected.
NOTE : As a rule of thumb, with the sun at 220°, I did each single displacement at 2%
horizontal and 5% vertical parameters.
Repeat the displacement filter
1 to 4 more times until you are happy with the result. Keep in mind the vertical angle you gave
to the sun: in the evening, shadows are longer. (See the Advanced part for finer
enhancements)
IMAGE > APPLY IMAGE : add channel
Forest2 with invert. This removes the forest and keeps the shadows.
Apply the shadows
Go to the ProjectShadow
document.
SELECT > LOAD SELECTION : choose Untitled-1 document, load the ForestShadow
channel.
EDIT > FILL with black.
Darken and emboss
One can observe in reality that any type of forest looks much darker than fields, grass or
towns. I suggest to paint it a bit darker. (See also Advanced part).
NOTE : For this purpose, you may prefer to modify the base TerraScene textures.
Finally well add some emboss effect to the forest. We do these steps on the
ProjectShadow document.
Create a new layer (GreyLayer)
over the shadow map. Fill it with neutral grey (brightness=50%).
Note : This layer will capture the lightning effects applied on the upper layer. I found this
way to eliminate some weird bright spots inside the deep mountain shadows.
- Create a second new layer (EmbossLayer) on top of the others. SELECT > LOAD
SELECTION : Forest2 from Untitled-1. Fill with a dark grey (here Brightness=25%).
LAYER > EFFECTS > BEVEL
AND EMBOSS. Choose the Emboss effect. You can play with Opacity of shadow
and light, or keep the defaults. Use the same angle you entered in TerraScene for the direction
of the sun. Merge down this layer with GreyLayer. (Blending mode : Normal)
Set blending mode of GreyLayer
to Overlay.
And its all done for the forest!
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