Basic Concepts
From ZBrush Info
Contents |
The Pixol
ZBrush can act as a hybrid between a 2D and 3D program through its innovative pixol technology. In other programs, points on the canvas – pixels – just have color. In ZBrush, points on the canvas also have depth, material and orientation information; these special points are called pixols.
When pixols are rendered the information about their distance, orientation and material is used as well as their color - with impressive results. Paint strokes can be given the appearance of metal, wood, concrete, mirrors or of many, many other things. What’s more, a change in position of the scene lights will affect the shading of everything on the canvas, to dramatic effect.
You can think of pixols as 2.5D - a combination of the simplicity of a 2D painting environment with the power of 3D.
ZTools and the Edit mode
As explained at the end of the previous chapter, ZTools are the elements you can use to create an illustration. All Tools provide a method for adding pixols to the ZBrush canvas or modifying pixols already there. After selecting any Tool such as the Sphere3D primitive, you can draw it on the canvas by clicking and dragging the cursor. (Keep in mind, however, that some Tools such as Blur modify pixols already on the canvas and will have no effect if used on a blank area.) If you repeat this click-drag action while the Sphere3D Tool is selected you’ll get a new sphere; continue again and again and each time will create a new sphere.
After releasing the pen tip or the mouse click, what you last drew is in a waiting state while ZBrush watches to see what you do next. At this point you can Transform what you just drew by using the Move, Scale, Rotate or Edit options. This allows you to modify the last stroke that you drew, or edit your model in 3D mode. If you do anything other than select one of those four options (for example, if you select a different Tool or make another canvas stroke) then your stroke becomes permanently fixed to the canvas. If you’ve drawn a series of spheres, you won’t be able to select any of your previously drawn spheres: they have been dropped to the canvas. They are now 2.5D pixols and part of the global illustration.
This dropping to the canvas will happen with any 3D model, either one made inside ZBrush or imported from another software package. But don’t worry; if you want to work on a model in its 3D form all you have to do is switch on Edit mode immediately after drawing the model. Then you will have access to all the 3D sculpting and painting tools. And if you should accidentally turn off Edit mode while working, your 3D model will still be available in the Tool palette; simply clear the canvas (or press Ctrl+Z if you only want undo the last thing you drew), re-select your Tool, click-drag to draw it on the canvas, then turn on Edit mode to continue working.
This transform capability is also useful with paint strokes. While you can’t use Edit mode on a stroke, you can use the Move, Scale and Rotate functions to activate the Gyro, which lets you transform the last thing you drew. You can even change the color and material that were used to create the stroke.
Another useful feature that relates to this topic is the Transform >> Snapshot button. Use this when you want to make an instance of whatever you are currently transforming. For example, you can draw a Ring3D and activate Move. Click Snapshot to make a copy of the ring in its current position, then move the ring to another place on the canvas and change its color, rotate it, or make any other transformations. This is a great way to make copies of the same object or brush stroke without having to keep drawing it over and over again.
The Canvas Document
As explained in the introduction, ZBrush isn’t quite like other 3D packages because of its 2D elements: It doesn’t have a 3D scene, but rather has a 2.5D canvas document on which you can draw 3D objects. Many of ZBrush’s signature and most powerful features are made possible by the fact that ZBrush uses a canvas rather than a full 3D space.
The Zoom controls act on the canvas, enlarging the pixols. So if you zoom in far enough, you will start to see the individual pixols and the image will lose definition. It is just like enlarging an image in a photo editor.
When you are working on a 3D model in Edit mode and want to get in close, you don’t use the canvas zoom. Instead you Scale the object. Scaling the object means you’ll be able to get in as close as you want and work on tiny details without any loss of definition. Note that scaling doesn’t change the true size of the object; it only affects how much of the canvas your object takes up.
Saving Tools and Documents
When you are working you are sure to want to save your creations. That’s when it’s important to remember the difference between the canvas document and your 3D models. The document can only contain 2.5D pixols, and so does not contain the full 3D data of a model. So if you are working on a 3D model and save the document, only a pixol version of the model in its current view is saved. That’s no good if you want to continue sculpting next session. You must save your 3D model through the Tool palette. You can also save all of your ZTools at once by using ZBrush 4’s Project feature. (See below.)
To summarize:
- Saving the Document will save the canvas 2.5D content only. This is used for illustrations.
- Saving the ZTool will save the selected 3D object (including all its subtools, subdivisions, settings, 3D layers, etc.). This is used for models.
- Saving a Project will save multiple ZTools at once. It results in a much larger file size and so is not a good choice for saving on multiple versions of a single ZTool.
Most users will save the ZTools and not the Documents if they are using ZBrush only for its 3D features.
Expert Tip: Please get in a habit of saving your work often and incrementally. ZBrush is a very demanding application, pushing huge amounts of data. Computers are not perfect and even a slight error can create problems such as corrupt files that cannot be reloaded. Saving your work every hour or so will prevent losing a lot of time and effort should the unthinkable happen. To be as safe as possible, it is also recommended to save under a different name each time so as to maintain three or more increments just in case something goes wrong with one of the saves, corrupting it.
ZBrush Projects
New in ZBrush 4 are Projects: when saving a project, ZBrush will create a single file that includes all the loaded Tools, canvas document information, Timeline animation and more. In essence this is a simple way to save your whole ZBrush session, so that at a later time you can reopen it and continue your work exactly where you left off.
To save a Project go to the File palette and press Save, or hit Ctrl/Command+S on the keyboard. You can open a project at the same location or by hitting Ctrl/Command+O.
Please keep in mind that when opening a project, any currently loaded 3D Tools will be deleted! Also, Project files can become extremely large.
2D and 3D navigation
As explained in the introduction, ZBrush mixes both 2D and 3D; as a result it has both 2D navigation and 3D navigation.
On the top right of the default ZBrush user interface you will find the 2D navigation, which is close to what you will find in photo and other image editing software:
- Scroll: Click and drag on this icon to pan across your document.
- Zoom: Click and drag on this icon to magnify in and out your document interactively like in other 2D editing packages. Note: some beginners use
this tool to zoom in 3D, which is not its purpose. At high zoom the pixels of the document are very visible.
- Actual: Click on this icon to returns the canvas to its actual size, or 100% magnification.
- AAHalf Mode: When this icon is pressed, it sets the zoom factor for the canvas to exactly 0.5, or 50%. ZBrush treats this scale factor in a special manner; when the zoom factor is exactly 50%, the canvas contents are antialiased which reduces the “jagged” effect that can appear along edges in a computer-generated image. Many artists create their documents at twice the desired export size, then activate AAHalf before exporting the rendered image.
ZBrush 4 also introduces a new Best Preview Render (BPR) mode that can replace AAHalf and produces spectacular effects like SubSurface Scattering and ambient occlusion. See the “New Features” documentation for more information on this powerful feature.
Underneath these buttons and those for perspective and grid display, you will find the 3D navigation buttons. Some of them are just modes while others are direct actions. They will only be active when a model is in Edit mode.
- XYZ Rotation mode (on by default): When set, rotation of the object is unconstrained so that it can be quickly spun on any axis.
- Y or Z Rotation mode: When set, moving the mouse horizontally will cause rotation only around the model’s Y or Z axis. Moving the mouse vertically will cause the object to be rotated around the screen’s horizontal axis. This makes it easy to rotate around the model’s Y or Z axis, while still giving flexibility in positioning the model.
- Frame: When this icon is pressed, ZBrush will scale the current Tool in order to make it fit the viewport space. The shortcut is F.
- Move: Click and drag on this icon to move your 3D model inside the document. This operation is similar to a 3D pan in other 3D software.
- Scale: Click and drag up or down on this icon to resize the model within the viewport. This allows you to show the whole model at once or two scale
it higher so that you can get a good view of fine details. This operation is similar to moving the camera closer to or farther from your object in other 3D software.
- Rotate: Click and drag on this icon to rotate your 3D model inside the document. This operation is similar to orbiting the camera or point of view around an object in another software. It won’t affect the real rotation value of the vertices of the model (the model’s local coordinate system). When doing a rotation, you can press the Shift key to do 90° constraints.
Create concepts in 2D
Before starting your first creation, don’t forget to think about it first, even if only for a couple of minutes. A good preparation and understanding of your concept will help you later in the sculpting process. Sometimes, a simple 2D sketch can be very helpful and perhaps save time later.
For this purpose, ZBrush offers two plugins:
Quick Sketch which as its name says is a quick solution to sketch out your ideas. It uses a few brushes located in the Brush palette, starting with the “Pen” name.
Just click on the Quick Sketch button located on the top left of the ZBrush interface and start drawing. You will notice from the first stroke that symmetry is enabled. To disable symmetry just press on the X key or go to the Transform palette and disable the Symmetry mode.
When you are done with your drawing, you can save it as a Tool or a Project. From there you can load a new project to start your sculpt in 3D or reset ZBrush by going to the Preferences palette and clicking the Init ZBrush button.
PaintStop is a plugin that will temporarily replace the ZBrush default interface and transform it into a full painting software. As mentioned in the introduction of this Starting Guide, ZBrush is also a 2D program, capable of being used to paint beautiful illustrations!
PaintStop is designed to mimic real-world media. Draw with different pencils, continue with oil painting, crayon, pastels, watercolors and more to perhaps create more than just simple 2D concepts!
To launch PaintStop, go to the Document palette and click on the PaintStop button.
You can find the PaintStop documentation in the Documentation folder in your ZBrush directory.
