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Foliage: Introduction - Images - Features - Videos - User Notes
Introducing Optipustics Gen 2a growing generation of 3D Particle brushes  <<< Click image to enlarge Way back in the 90's, we made something of a splash with Optipustics, our particle drawing tool. While the name covers a variety of technologies including animatable particles and bristle brushes, it is best known for its particle foliage drawing tool. The original particle drawing is still there. Optipustics 2 is an addiction to, not replacement for particle foliage, and exits in a new foliage tab on the particle panel. The new Foliage tab is a dedicated foliage drawing tool, while the original could double as a particle system for animation. Here are a few of the design concepts that were integrated into the new tool: The new system is based on a library of rules, to allow for each branch to have its own rule including dynamics such as velocity and gravity. This makes branching structures much more flexible. It is a fully 3D gag,
internally speaking. Transformations such as
rotation and scaling should thus be possible in
the future, along with more complex dynamics. Stay
tuned for updates. The new system is able to generate depth and alpha channels. Other channels may be possible in the future. There is a real-time
preview. Final rendering has been moved to a
post process to allow for more complex rendering
gags to be accomplished than were previously
possible, or to account for information that isn't
initially known at draw-time, such as final
volume.
Images
Here's a quick look
at the secondary interface, i.e. the Foliage Rules
Library:
In the top left you
see the current Rule, namely rule number 2.
Essentially, the system offers a list of several
rules. The more rules you define, the more
sophisticated the foliage system can become. But
it also depends a lot on what exactly each of the
rules say. You can specify the color, whether the
branch will split and how, at what speed it grows
and which way, and which way gravity changes it.
It's not just up-down or left-right anymore, such
as it is in the original particle brush system.
This is now a fully 3D environment, so you see
such things like the velocity, damping, or the
gravity vectors defined as full 3D values, x, y
AND z! Like in the original
particle brush system, you can still also indicate
how strongly to follow the mouse, which is great
for manually 'painting' the wind-blown reshaping
of bushes and trees (such as for Torrey pines or
tall tufts of weeds). Don't worry though,
if this seems a little bit overwhelmingly too
complex, we have included some nice Presets to get
you started.
Presets: The Rules library is
for those who For all artists who
just want to paint, we have included a collection
of presets. You can simply click "Load" at the
bottom of the panel, and find a great preset to
start from. Then you can also
further fine-tune and modify the parameters in the
rules, or add more rules, and save your changes as
a new preset. <<< click
the image to enlarge
Animating Animating a growth
via the stroke player's “Hancock” mode is now a
reality as you can see in the first video at the
top (scrub towards the end of the video). We'll
have examples here shortly.
Here are just a few pictures to give you an idea. Some contain combinations of Particle and Foliage system. Scroll further below for sample videos as well.     Basic Tree foliage:
 Comic book
trees
 Dry stuff:  Foliage painting, on basic netbook:  Features, Options & Parameters The Time scale option enables size reduction of features towards the top and tips.  Post-render pass (secondary rendering): here's a comparison of what you might get immediately at the end of a single(!) brush stroke, and shortly thereafter, when you wait for the final secondary render that ensues.
click images to
enlarge either one of them
Videos How to draw a tree in seconds, wish just one brush strokeThe Language of the TreesUser Notes Most of the time we just recommend this: try it, find out, make mistakes. But sometimes, we need an explanation. The Foliage system is a non-recursive particle system that uses a library of Newtonian rules. There. Not sure if that helped. There can be just one rule or there can be more. Rules are there to tell the particles what they can do next: what color they can assume, where they move to, if they're on their own or affected by gravity or even follow your mouse motion, if they keep going or split, branch alternatingly, or die etc... Note that the main panel has some significant parameters too, such as the Rule count. You may have defined a certain number of rules, but the global rule count value will limit how many are actually usable at the moment. Also note that most parameters have a tool tip when you hover and rest over their input items. ----- Globals (in the main panel): ----- Max parameters: the maximum number of particles to process at one time. Reduce this value if you're on a very old/slow system or gasping for RAM. Or just to test things a little faster as you play and explore, before going back to final settings. Rule count: the number of rules currently in effect. Even if you have more defined (there is room for more), this is how many it will attempt to use. When a particle branches, the next rule is installed. Max lifespan: the maximum number of steps to be taken to process all particles. Tint color: click this box to select a color that will multiply (thereby creating a tint) to the RGB values of the particles. Unlike with the color cue option, the effect is the same regardless of whether you use the left or right mouse to draw. This is a great way to quickly assign a more lush and fresh look (greenish) or dry and old (reddish). Fog color & Fog amount: You can use it to make plants come close to the selected color. The value slider below it sets the intensity of the fog. If you draw multiple plants, this trick can be used to convey 'distance perspective' that makes the objects fade to the far distant color such as blue haze, or perhaps to black at night. The farther away you want the tree to appear, the stronger the fog effect should be. It's also called a depth cueing trick. Gain: sets the lightness of the overall plant. From 0 to 1, generally, but can also be greater than 1, in which case it'll be really bright. Pen size: this value is in pixels and affects the size of the particles that are rendered as they go on their journey. Time scale: you want this. Well, most of us do. Branches are getting smaller and thinner towards the end and near the top of trees, don't they? In the older particle brush system, there's an "age decrement" parameter (since v4.1). think of something like that. Shading: This enabled a lighting effect, by darkening the particles that grow down. The idea is that the ones up above are exposed to more sunlight (and even just sky light), whereas the branches down below are in their shade. Color cue: instead of taking the color cue from the above-mentioned Fog and Tint color boxes, use the primary and secondary colors, i.e. colorize one or the other way depending on whether you use the left or mouse button to paint it. Create alpha: we can do more than set the color of all pixels where particles are rendered. We also set the selection mask, in the alpha channel. At the end of it all, you'll have a beautifully anti-aliased selection mask that contains the plant. Use control-B for example to pick it up as a custom brush (or use the option at the top of the Brush menu - use selected as brush). The sky's the limit, the alpha channel is the means to it. Seed and Rnd: things need to look somewhat randomized, and a random nuymber generate likes some seed value to start from. Click the button to get a new one, so the next plan will look even more different. You don't want that however if re-rendering (with Ctrl-A) and you want the exact same shape (just perhaps different colors). You also don't want that when doing a re-render in the stroke player for an animation to show up consistent with the way you saw it initially. Autoseed: keep it enabled. You really will want that. It doesn't affect the seed when using the stroke player to re-render. But you'll be happy it does it for you when doing normal brush strokes. Then again, who knows? Rules library: edit the rules library used to control the growth and evolution of the particles, and blame it on this little button when it's past 3 am and your significant other is asking why you're still at the computer. Be warned, this is a point of no return. ----- Parameters in the Rules library panel: ----- Emmit count: The number of particles that are emitted when the current rule (branch) is started. Branch lifespan: The number of steps that the current branch is processed. Repeat rule: The number of times the current rule is repeated for the current branch (starting at 0 repeats) before a new rule is started, or the branch ends. Red/Green/Blue: The color of the current branch (may be above 255) Follow mouse: Usually used for the first rule but may be used for others. This causes the branch to gravitate toward the current mouse coordinates. Sometimes it can yield a "wind blown" appearance. Try drawing a half circle with or without a significant value in this parameter to see the difference. Values are usually between 0 and 1, and something like 0.5 works well. Very low values (0.001) can give a smoothing effect, while still roughly following the mouse motion. Gravity x,y,z: This is a negative vector that is added to the particle at each step. In other words, this is the incremental change. For example, a value of y=1 would add -1 to the velocity at each step. And yes, this is a fully 3D system. Velocity x,y,z: In contrast to "Vector x,y,z" mentioned below, this is a range setting for initial velocity. The value may be any value in-between its positive and negative. For example, a value of 1 for any of these parameters would cause a random value anywhere between -1 and 1 to be generated. The initial velocity is then set to this value. Vector x,y,z. Adds this value to the initial velocity. For example, use -1 for y to cause a branch to start growing upward. Split type: This is the type of branch to create when the particle lifespan has been reached, and it has completed any repetition of its rule. Basically answering the question: what now, what's next? The type can be no-branch, branch, branch even/odd, split, and end.
Damping x,y,z: This value is usually between 0-1. The velocity of the current particle is multiplied by this value before the next rule is started. This can be used to reduce velocity as a new particle is emitted. Oh yes and there may be a few more, in time. |
