|In this tutorial, we'll
play with some of the settings starting from the preset called
You can select it from the Settings area on the Particles tab.(bottom
or also in the Particles menu from the Presets button (upper left).
|Draw a quick brush stroke.
Here's what it might look like a second later
||Let's start playing with
some of the parameters exposed in the Particles tab:
For example, if you plan on creating an image of a plant for texture
mapping in 3D programs, you might want to have it generate the Alpha
channel data on-the-fly too.
Instead of the 'Line' style, select the Style named 'Line + Alpha"
With this style selected, particles will be drawn as fine lines and
with an alpha selection mask 'around' them.
||Use 'u' to undo, or
Or, to simply clear the current image buffer, click the big 'X'
icon amongst the drawing tools.
You can also find additional options in the Edit menu, and a keyboard
shortcut (Shift-K, for 'Kill')
If you right-click the 'X' icon you will see even more options to erase
to white or black, or to erase just the selection if there is one.
By default, PD Particles clears to the secondary color.
||Now draw again, and you'll
see marching ants indicating a selection mask in the alpha channel
around the painted particle branches.
In the menu bar (top of the window), PD Particles shows '(Alpha)' to
remind you that there is a selection mask present in the alpha channel.
||Select yet another Style,
such as Shrinking Lines, or if you need the alpha channel generated
too, use "Shrinking Lines+" (meaning shrinking lines + alpha)
Shriking lines start with an initial size and shrink from there.
|The Size slider can then
be used to set the initial size of the particles. They'll start with
that size and then shrink down to zero size along their lifespan.
This can easily be used to draw several versions of branches in
the same tree or also to show different thickness based on distance, to
support perspective effects.
||The Lifespan can be
increased if you want the branches to appear longer, or the overall
bush to grow taller. This is the lifespan of each branch.. Partgicles
can split (according to the splits count and angle). The Lifespan
controls the length of one such split branch. If you increase the
number of splits (with a given and fixed Lifespan), then the total
length will grow too.
||Here's an example using
shrinking lines plus alpha.
The branches appear thicker at the heart of the stems. But they appear
still a little too symmetrical and 'perfect'. We will want to add some
randomness to that set of parameters, so that the angles, lifespan and
other parameters can vary across the generated bush, giving it a more
||Here's another example,
with longer lifespan or more splits, can you find what changed in the
There are many other parameters and effects to lay with, such as 'Drag'
(try a negative value, or between 0.0 and 1.0, or a value larger than
||Changing Colors with
the Color Gradient
Note that the branches all appear a bit dark with the initial presets
from 'Winterbranches'.... The colors of the particles are affected by a
color gradient, which in this example starts very dark all over. You
can select a different gradient index (8 are available from the current
Or, you can change the currently selected gradient.
Click the color gradient bar (which appears all dark in this example)
||Select one of the color
tabs (Red, Green, Blue or Opacity) to indicate which color channel you
want to change. Then you can interactively change its progression
across the gradient. Left to right corresponds to the color evolution
from start to end of a particle's life.
In this example, particles would start dark red, go through dark green
and end up dark blueish.
Here we're adding a little more green towards the middle, after having
raised the red and blue levels a little too in the left and right parts
of the gradient.
Notice also that you can drag-and-drop colors from the color Wells.
Drop them into the scale near the bottom of the gradient window.
There are several gradients to choose from.
Gradients are very powerful and can be used to create numerous effects.
Not only can you modulate color but also the opacity (or its
counterpart, transparency). Grass can become very thin when opacity is
reduced, for example. At the end of a thin grass helm, if you suddenly
change to full opacity, it may appear like a flowery tip.
This is great for thin hair too.
Painting with it now, we see a little more color and tones in the
Notice also that overall you can tint the branches. Check the checkbox
named 'Tint'. Then select a different color from the color swatches or
color wells and wheels. The primary color (selected with the left mouse
button or tablet pen) is used as a tinting control color, thus making
it a snap to add a more dry orange look or a wet green look to the
There's also a Fog option. Fog is 'added' as a color, whereas tinting
is a multiplicative operation. Tinting is great for quickly having
slightly different versions of the same base tree.
Here's one example that
was painted in just a few seconds.
(Click for the large original image at HDTV resolution)
This can be great to create new images for use as environment maps in
games, or as
surrounding background images in global illumination rendering with
Carrara and other 3D programs
There are also a few filters for color correction. You could remap
colors to a color gradient too,
or use the color adjustment filter to make it look like a winter scene:
||Saving your work
Remember the saying: save often.
Save this image to a Default Targa (*.tga) format...
||You may have noticed that
Windows Explorer is able to show the thumbnails of .tga image files in
our example. It doesn't normally have that capability, but you can load
an extension that adds it. It is from Greggman and a free download
amongst other plugins found for Project Dogwaffle (some of which, but
not all, can also be used with PD Particles).
Make sure you use the 'Default Targa' format. There is another .tga
option in the 'Save as type:' menu, but it may not offer the option for
the Alpha channel to be saved too, or to the contrary it may save it
when you don't want it.
The best and safest format to save to is the Default Targa format.
||The 'Default Targa' save
option will present a dialog to let you specify the pixel depth. Be
sure to choose 32-bit if you have alpha data which you wish to save too.
Notice that after painting something with alpha, if you simply clear
the image, that may not clear the alpha channel. You will be left with
the selection mask.
The alpha channel can be cleared independently and separately.
||Use the standard keyboard
shortcut, Control-D, to clear the selection (and hence the alpha
buffer). Or select the Clear alpha option from the Alpha menu.
You can also temporarily 'hide' the alpha by turning it on and off,
without really clearing it.
There are other options in this menu, so it's worth a few minutes
of playing and discovering. Another tutorial may explore this further.
from outside the Window
Sometimes, you want to start drawing from outside the active canvas or
image buffer's window. To facilitate that, you can either zoom out, so
that some grey'ish area around the active drawable region will then
Or, you can simply drag and enlarge the window containing the image
buffer. For example, click and drag the bottom or top border of the
image buffer's window.
||There is now a light grey
area around the white, drawable region.
This can be a starting point for your cursor when you start your
brush strokes. From there you can draw towards the inner parts, or even
stay outside near the border. Some of the particles will then break
into the drawable area.
||This helps in creating
bushes, tree and tufts of grass which start at the bottom of the image,
which helps when you want to paint alpha-mask enabled textures which
don't float in the air near the bottom of the texture. You can then
simply place the billboard polygon in a 3D scene on the 'ground' and
the painted tree will appear to grow right from it.
|Saving your Particle
After you've played with these parameters for a while, you may have
found the perfect setting for a new type of bush or grass, or a total
mutant diversion of it. If you like to use it again in the future, be
sure to save the settings.
Click the Save... button in the Particles tab near the Settings button
by the bottom.
||PD Particles saves
particle settings in files ending in .opt (Optipustics files).
Give it a new name and click 'Save'.
You can edit these files with a text editor such as Notepad.
(note: PD Pro can use particle brushes with animations)
After saving your new setting, you can immediately see the newly saved
.opt file in the Settings.
||For the newly saved
setting to also appear in the 'Presets' button and menu near the top
left, you will need to close and restart PD Particles.
Going beyond...with PD
Here's another look at the previous example, with added special fx for
dynamic range, Mystic vision and light diffusion.
These and numerous other animated fx filters are part of PD Pro's animation
PD Pro also can turn this into an animation: Flash - Avi - Avi(xvid) - Quicktime