Lesson Two - Basic Training, Part One (Painting)
Welcome to the second lesson in the New Users Series! Meant to teach new users the basics that will allow them to get up and running quickly, this lesson will deal with the basics of 2.5D painting. Other lessons in this series so far are:
In this lesson we will cover two main areas. First, we’ll take a look at exactly what it is that you’re painting with when you work in ZBrush: the Pixol. We’ll see how it works for you, and all the different factors that go into what you see on the screen. By understand this, you’ll have a better grasp of how revolutionary ZBrush is, and how to make that work for you. The second part will put this knowledge to work, and will pay special attention to the very hub of ZBrush – the Draw Palette.
IT’S ALL IN THE PIXOL
You undoubtedly already know what a pixel is – a single point of color in a picture. All raster images (as opposed to vector graphics) are made up of pixels. Simply put, a pixel contains a single point of color, along with the XY coordinates for where to put it in the picture.
When you paint in a ZBrush document, the program goes way beyond that. In fact, the differences are so dramatic that Pixologic coined a whole new term for it! Each Pixol contains the same info that a pixel does – color, X and Y – but it also contains information on depth, orientation, material, lighting and more. All of these things factor together so that when you finally export your scene (and convert it to pixels in the process), these final pixels can have the most accurate color information possible. While you’re still working in ZBrush, this pixol information puts tremendous power at your fingertips. As we’ll see, pixols work together and actually interact with each other.
Let’s first take a look at how ZBrush determines what color each point in the scene is.
Diagram Courtesy of Pixolator
As you can see, ZBrush runs several channels. It starts out with the shape of whatever it is that you’re painting – whether that’s a simple brush stroke or a complex object. This is the XYZ coordinate of each pixol. Across the surface, it applies the color channel in the form of either pure color or a texture. Next, it adds in the material channel. Called a shader in some other programs, this information tells ZBrush how the surface reacts to light. As you can see, the color channel can be radically modified by the material! Finally, ZBrush applies shading based upon the lighting settings. Of course, this can further be refined by the rendering settings, but that’s a later lesson!
When you first start with ZBrush, it’s easy to forget about the power of materials. I remember that I never used them at all until Pixolator published a thread on how useful they could be. Then I went through a phase where I didn’t create textures at all! Any color variations that I wanted, I got from the material settings. The ideal place to be, though, is to use the materials to enhance your color and texture work. While a future lesson will deal with materials in detail, don’t be afraid to go into the Material>Modifiers and play with the settings.
As previously mentioned, the other part of the pixol is its XYZ coordinates, along with the orientation of each pixol (the direction that it points in space). Because each pixol remembers this information, painting in ZBrush becomes a matter of adding layer upon layer of detail. Each new pixol will interact with the ones that it is painted onto. A good example of this at work is to draw a sphere on the canvas and then add arrows to its surface. Each arrow will automatically point outward from the center of the sphere, because each cone takes into account the orientation of the pixols that it is being drawn on. You are also able to paint at various depths, allowing for nice effects such as depth cueing, fog, and realistic shadows.
COMPLEMENTARY PALETTES – Or, What’s in a Brush?
Now that you have a better idea of what you’re painting with on the canvas, it’s time to take a look at what you are using to do that painting. In Lesson One, I touched briefly on the fact that Palettes work together. Now it’s time to go into that in a little bit more depth.
Every time you click on the canvas, you are adding pixols based upon your settings in many of the different palettes. Based upon what has already been discussed in this lesson, it should be no surprise that Material, Color, Texture and Lighting should be involved. Also, the Tool palette controls the exact kind of brush that you are using – 2D, 2.5D or 3D. For many brushes the Alpha Palette controls its shape, giving the brush such characteristics as a hard or soft edge, or even a pattern of some kind. The Stroke Palette also comes into play, determining what happens as you drag your mouse across the canvas. Finally, helping to coordinate all of this is the Draw Palette.
That’s a whole lot of activity going on! This combined effect is what gives ZBrush its incredible power, but it is also the hardest part of the learning curve when you’re first starting out. It can be a little bit bewildering trying to remember what does what. Even worse, it can get frustrating trying to hunt for one Palette after another to get all the settings that you need for the effect that you’re trying to achieve. This is where the Float Menu will become your best friend. By having parts in it that allow you to select new colors, materials, alphas, tools, textures, stroke types and drawing modes you can put all of your most commonly used interface items in one handy place, available at the touch of a button.
Don’t be put off by how many factors are involved. Start by becoming proficient with one or two areas, and then expand your knowledge.
The Draw Palette – The Core of ZBrush
Every time you draw anything on the canvas, whether it’s a painted brush stroke or a 3D object, the Draw Palette controls the most fundamental parts of what’s happening. Let’s take a few minutes to look at the Palette in depth.
The top section deals completely with settings that affect the brush itself. X, Y, Z dimensions are all represented by the sliders, along with another to control how deeply your stroke will be buried inside of what’s already on the canvas. This last factor is handy when you’re drawing 3D objects, or when you’re using many alphas (allowing you to hide the sharp outside edges). Immediately below these settings is a preview of what the brush looks like. By clicking inside the preview, you can rotate it to see how the stroke looks against the flat plane that represents your canvas.
Below the preview is a slider for the brush size. Settings range from 0 to 128 with a default of 64. Using the Preferences, you can set this maximum value to be much higher, but you will have to type in any value over 128.
Next we have two sliders for intensity, with an L button next to them. The RGB Intensity slider determines how much color is laid down with your stroke. An intensity of 100 will be completely opaque, while lower settings become increasingly transparent. This can allow you to build up a lot of subtle blending between shades. The Z Intensity slider determines how much depth is added or subtracted with the same stroke. Again, the farther to the right the slider is moved, the more pixols you’ll be adding to the canvas. The L button locks both sliders together. While this is handy for many things, there will also be times that you want to turn it off so that you can adjust the sliders individually.
The next row of buttons is for perspective – a more advanced technique than this tutorial will cover. There are several good threads in the QuickLinks when you feel ready to delve into this.
Now for the real meat of the Palette! MRGB, RGB, M, ZADD, ZSUB and ZCUT are the buttons that you will refer to constantly. Only one button in each row can be active at any time, but you can also have none of them turned on. What you choose to do will be determined by your needs.
MRGB active means that you are painting with both color and material, using the intensity set by the RGB Intensity slider.
RGB active means that you are painting color, but not material.
M active means that you are painting material, but not color. A word to the wise: the more radically different your current material is from what is already on the canvas, the more dramatic the edge between the two materials will be.
ZADD active means that you are adding depth with each stroke, with the amount of depth being controlled by the Depth and Z Intensity sliders.
ZSUB is the same, except that you are removing depth instead of adding it.
ZCUT is essentially a Boolean operation. When painting in 2 and 2.5D, it’s really no different from ZSUB. But when you are drawing a 3D shape onto the canvas, this setting will cut the new shape out of the pixols that are already there.
By changing the settings of these 6 buttons, you have total control over what your brush will paint on the canvas. It is possible to paint with just color and no depth by having RGB being the only button that’s active. By having ZADD be the only active button, you’ll paint with depth but not change colors or shading. Other combinations will have different effects. It’s a lot of power!
The Channels menu is beyond the scope of this tutorial. It contains advanced functions that are rarely used.
I’m not going to go into a lot of detail about the Layers Palette at this point, but it is important to understand that it exists and what it can do for you. One thing that is very important to understand is that layers in ZBrush have very little to do with relative depth – they are simply a way for you to keep parts of the scene separate. In other words, objects and strokes on Layer One can actually be painted in front of, behind, or even inside of those on Layer Two. But when you paint on Layer One, you will not affect anything on Layer Two, even if your stroke goes right over top of whatever it contains.
An excellent example of this at work is if you’re creating a head. Draw the head on one layer, and put the eyes on the other. When you paint extra shading onto the eyes, you won’t have to worry about accidentally overflowing onto the skin. Or for that matter, you can choose to erase the eyes and paint new ones, without affecting the head at all.
You should be able to see that by keeping the main parts of your painting separated on different layers you can completely avoid having to worry about accidentally “coloring outside the lines” and affecting something that you don’t want to change.
It is also possible to move layers around on the canvas (similar to Photoshop’s Offset filter) for creating seamless textures. You can change a layer’s depth in Z space. And a very handy command is baking the layer, which changes everything on the layer to the Flat Color material, converting all colorations that come from things like materials and lighting into actual RGB color. This renders the layer impervious to shadows, allows the color picker to “see” the same colors that your eyes do, and makes for cleaner fiber brushing. You’ll see how all of this works later.
It should be mentioned that the more layers you have, the more processor power will be required to keep track of everything and the longer it will usually take to render your scene.
KNOW YOUR TOOLS
Although they are mixed throughout the Tool Palette, there are actually three major categories of tools. Let’s take a look at each type in turn.
3D Objects. These start out as polygons, which are then converted into pixols on the canvas by a process called the Snapshot. As you’ll see in Lesson Three, these can also be transformed in various ways to create entirely new objects of all kinds. When painting any of these onto the canvas, the draw depth will make a big difference – you can set a primitive to be all but buried beneath the existing pixols, completely standing out in front of them, or anywhere in between. You probably won’t use these tools in their primitive form too much (although there are certainly places where all are useful!), but if you’re like most ZBrush users you will soon be creating the main parts of your scene from modified primitives and then adding extra detail in using the other tools.
Pixol Adders. The vast majority of your painting will be done with these, which each add pixols to the canvas in a specialized way. By far the most commonly used is the Simple Brush. And while these brushes do add pixols, it should be remembered that they can also be used with different Draw settings to add just color or material instead. The Draw Palette can definitely blur the lines between the tools, leaving few hard and fast rules! Perhaps the most famous of these brushes is the Fiber Brush, which can be used to create anything from fur to hair to vegetation.
Pixol Changers. These brushes cover a gamut of uses, from enhancing the shading of your scene to one of ZBrush’s signature brushes: the Snake Hook. The MRGBZ Grabber is used to capture parts of the screen as textures and alpha/depth maps. And one of the wildest tools, the MultipleMarker tool, can be used to combine several 3D primitives into a single Polymesh. The basic rule for all of them, though, is that something must already be on the canvas in order for them to work.
As these lessons progress, the various tools will be used throughout so that you can get used to what each can do. One very important point to remember, though: Only tools that fall into the first category – 3D Objects – can be saved as .ZTL files. You can’t, for example, make a tentacle with the Snake Hook and then save that as a .ZTL. Since .ZTL files are also known as “Tools,” it can get a little confusing! In order to try and keep things clearer and easier for you, I will from here on refer to 3D Objects as “Tools”, Pixol Adders as “Brushes” and the Pixol Changers purely by their name.
The written part of this lesson has been meant to introduce you to the various concepts that fit together to form your painting experience in ZBrush. It’s much easier to get the results that you want when you know why things happen or what’s possible!
The ZScript will actually show you these concepts in action, and will especially focus on putting them to use in the creation of an actual scene. It is recommended that you study both the written portion and the ZScript, as they are truly meant to complement one another.
In addition, the script is written in such a way that you can go through it twice. The first time, read along and let the script do the work for you. The second time, use the text as a guideline to try the techniques for yourself. Please feel free to post your results in this thread!
:red_circle: :large_orange_diamond: :small_blue_diamond: [Click Here to Download (560KB)](http://pixologic.com/users/matthew/tutorials/LessonTwo.zip) :small_blue_diamond: :large_orange_diamond: :red_circle:
Once downloaded, you will need to unzip the folder into your ZScripts folder. (If you’re on a Mac, you’ll need to place the entire contents of the folder into the same folder that contains your DefaultZScript.txt file.) Then use ZBrush to load the Index.txt script.
Lesson 3 will teach the basics of modeling both organic and mechanical objects. ZBrush is great for both, but the techniques between the two can be very different.