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In this 2-part tutorial
we'll use Poser 6 to add some backdrop rectangle in the back of a Poser
figure, and another in the front. Both polygons will carry pictures
(textures) of foliage created in PD Particles.
The background polygon will simply carry an opaque image. The rectangle
in the front will need to have some transparency mask to keep the
foliage opaque while the rest around it remains transparent.
Some 3D programs are able to use the alpha channel from an image where
the alpha channel contains the transparency mask. Poser 6 uses a
separate transparency channel, so we'll need to create two separate
files - one with the color and one with the opacity ask.
Let's start by creating a new image, perhaps a square shape of 800x800
pixels.
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Note that some parts of
the image may not be visible if it is too large to fit in the window.
For example, a screen set at 1024x768 pixel resolution will not show
all 800 vertical pixels.
To see it all, zoom out or fit the image into the window with the tool
in the Zoom tools group, or function key F4.
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We'll want to clear to
black. Right-click the erase icon (X) to clear to black. Or,
drag-and-drop the primary color into the secondary color in rder to
swap the two.
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Note that if you did
earlier select the black color from the color well, that it in fact is
not totally black. Red, Green and Blue are
If you want that color to be totally black (RGB=0,0,0) , enter the
value 0 (zero) in the numeric fields or slide the sliders to the left.
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That totally black color
is now in the primary color.
Drag-and-drop the primary color into the color well, such as over the
first 'black' cell, to replace it with the new black.
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Same thing with 'white',
the second cell. It is not plain white, RGB values are at 240, not 255.
If you want it totally white, set the sliders to 255 and drag-and-drop
the new white into the desired well's cell.
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Now let's start drawing.
Pick up the Particle brush 'SeriousGrass2'.
However, let's change a few parameters.
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Here is the list of
parameters.
Paint a few strokes to make a piece of shrubbery that stands on the
bottom and stays safely away from the other image borders.
Note that we could have used one of the styles with Alpha (such as
Shrinking line+), if we were going to use the resulting image directly,
with the opacity mask in the alpha channel from the same single image
file. In this example though we'll try to save the image's colors
separately from the opacity mask, so we can do without alpha.
< click to view the full image.
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Save the image with the
Default Targa format, making sure that the file name will allow you to
recognize it as the color image and distinguish it from the opacity
mask (which will be an 8-bt greyscale image, or perhaps 24-bit but
still a greyscale image).
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Select 24-bit depth.
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Now that the color part is
saved, we'll use the image to generate an opacity mask for it.
Typically, this is where your other imaging tool might come in, as
you'll be working with filters to enhance contrast, set thresholds or
increase value or gamma. You might even want to paint on the image to
turn some areas 'opaque' or transparent.(white or black, for instance).
PD Particles has however a few basic color filters and tools that may
be just what you need to do the work right in here.
Let's start by turning the image to a greyscale. Use the color gradient
(keyboard shortcut 'p' or menu: Window->Gradient...) and click the
'Gradients' button to select the Default gradients (Def_gradients). The
first one in that set is a greyscale gradient going from black to white.
Another technique would be to save the color image to .Default Targa'
format as an 8-bit greyscale, and then re-load it back in.
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With the greyscale
gradient loaded, select the menu:
Filter -> Color -> Map to current gradient.
This will turn the color image to a greyscale.
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Next, we'll use some
filters to adjust contrast and brightness to try and make it a more
opaque mask inside the foliage.
Select the menu:
Filter -> Adjust -> Value...
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(Note: the "Hue / Sat /
Value..." filter in the same group could also be used to make a
greyscale, by reducing the saturation to zero.)
Here's the 'Adjust value' filter. Four values to play with:
Value
Brightness
Contrast
and Gamma
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Adjusting Gamma...
If we move the Gamma slider to the left, it may saturate the 'inside '
of the foliage to full white, but may grow to the extremeties of the
tips of the foliage a bit too much. This may end up showing as colored,
white or black borders around the edges of the particle traces.
(depending on the background color at the time of painting the
particles).
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... or Contrast...
Adjusting the Contrast is recommended. The greyish tones inside the
foliage should all turn white to indicate full opacity.
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In the end, you'll want to
experiment with several of these parameters: Value, Contrast and Gamma.
In some cases it may not be possible to simply use filters to create
the right mask of opacity. You may need to paint on nthe greyish areas
to fill them to white if it is to be opaque. (Greyish would indicate
semi-transparent.)
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You could run the filter again and further increase the 'Value' to make
pixels turn white or stay black for either fully opaque or fully
transparent (if that's in fact desired!).
This will create a greyscale image suitable as opacity mask for the
foliage.
Save the image to 'Default Targa' and save it as 24-bit, or 8-bit
greyscale.
Either should work with Poser 6 or other popular 3D programs.
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