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Modeling a head in zbrush
Modeling a head in zbrush
admin, added 2006-03-31 17:19:58 UTC 200,978 views  Rating:
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NTRODUCTION TO ZBRUSH

To me, Pixologics Zbrush lives in a world somewhere between 2D and 3D never really knowing which camp to lie in. With it I can create 3D meshes that can be textured and have native materials added to them. Zbrush uses a technology called `Pixols` that sees each pixel as a 3D image that retains width, height and, more importantly, depth information. Once you `snapshot` a model (or Ztool) into an image you can still add depth with a number of brushes, change the model's material and even adjust the lighting. In this tutorial I will attempt to walk you through the creation of a detailed head study (called `EFXterminator`). The steps will lead you through modelling the head from a basic 3D sphere, adding colour and material to the model then creating and adding textured eyeballs. Finally, we'll model the hoses and metal parts of the image before moving on to lighting and rendering. The steps I describe are not the only way to achieve things in Zbrush.

It is such a versatile program that you can find a multitude of ways to do the same job. I used Zbrush 1.2 to create this image with a document sized at 2500x2500 with three layers. It is possible to re-create this image using the demo version. However, some of the settings and sizes may vary. I use a 1 gig AMD-based PC with 512mb of RAM and Win98.


MODELLING BASICS

Figure 1.

To start off this modelling session you need to understand a little bit about the TRANSFORM panel. (See figure 1.) The following steps apply to any 3D object or primitive that you can select from the TOOL panel. To model an object you need to place it into the document window. To do this, with the tool (model) selected, click into the window and drag out an object. To move, scale or rotate the object you can use the panel or press key `W`, `E` or `R` respectively. When pressing any of these keys a multi coloured `gyroscope` appears. Try each of the modes to get used to using the gyro to get the desired result.

TIP: To `move` along an axis, pull the coloured end of the gyro. To `scale`, click inside the gyro and drag up or down. To rotate, click inside the gyro and drag in the desired direction


To model or shape the object into the desired shape you need to enter the EDIT mode, press `T or use the transform panel (Figure 1.) When in the EDIT mode the cursor turns to a red dot with a ring surrounding it. The red dot is where your changes will be made on the object as you model. To rotate the model in this mode click while holding the cursor away from the object and drag up or down. Different effects can be achieved using the transform panel by clicking `draw pointer` (add depth to the object or remove it by holding down ALT), `move` (pull or push an area of the object) and `scale` (increase or decrease in size an area or polygons). (See figure 3.) To enlarge the `area of effect` on the object go to the DRAW panel and adjust the `DRAW SIZE` slider up or down. You will notice that the red ring grows or shrinks helping you to judge the size. In the DRAW panel you will also find `RBG Intensity` and `Z Intensity` which affect the amount of colour and depth applied to the object as you model. At some stage you may need to turn `colour` or `Z` (depth) off. This is done by selecting or deselecting the correct box (green is selected, grey isn't). These steps are the basics of constructing any 3D organic model in Zbrush.

TIP: The best results are achieved by keeping the `Z Intensity low when adding depth or pulling a portion of the model. This will let you subtly adjust the shape stage by stage using the different tools.

Now is a good time to tell you about `snapshotting`. A model (Or ZTOOL) in Zbrush is `live and editable` in the document window until you `snapshot it into the image (Press CTRL+S or the `camera` Icon shown in the transform panel in Figure 1.). Once you `snapshot` a copy it is no longer editable and cannot be moved or rotated. It does, however retain its depth information and can be modified with some of the 2D tools (Simple Brush, Blur Brush etc.) The original ZTOOL remains in the TOOL panel and can be saved as a .ZTL (Native format) or exported as an .OBJ or a .DXF Losing the facility to modify 3D objects was one of the first hurdles I came across in Zbrush. It is such a departure from the norm that it takes a while to feel comfortable with it, when you do, it becomes second nature and going back to being able to rotate a wireframe whenever you like seems weird.


MODELLING THE HEAD

Start Zbrush. Go to the DOCUMENT>MODIFIERS panel (usually on the left) and adjust the document size to Height 2500, Width 2500 (if you have the demo you will be limited to 640x480). Select `PRO` to allow you to adjust the proportions. To begin modelling go to the TOOL panel and select the Sphere3D tool. Click TOOLS>MODIFIERS>INITIALIZE and change `Hdivide` to 512 and `Vdivide` to 256. This will give us the maximum possible subdivision count for this object (lots of polygons).

Start Zbrush. Go to the DOCUMENT>MODIFIERS panel (usually on the left) and adjust the document size to Height 2500, Width 2500 (if you have the demo you will be limited to 640x480). Select `PRO` to allow you to adjust the proportions. To begin modelling go to the TOOL panel and select the Sphere3D tool. Click TOOLS>MODIFIERS>INITIALIZE and change `Hdivide` to 512 and `Vdivide` to 256. This will give us the maximum possible subdivision count for this object (lots of polygons). Click in the document window and drag out a sphere leaving plenty of space around it. As we are only modelling the head at this stage the position doesn't actually matter. At this stage we want to go straight into `EDIT` mode so press `T` on the keyboard and a red dot/ring will appear. Because the head we will be modelling is fairly symmetrical we need to turn on `symmetry`.

Go to TOOL>MODIFIERS>DEFORMATIONS>SYMMETRY and select `X`. You will now have two dots on the model. Any change made to one side of the model is exactly duplicated on the other side saving you a lot of work. Figure 2. To begin the modelling you will need to `pull` the Sphere into the basic head shape. Select `Move` (W) and pull the bottom of the sphere down. If the effect is too dramatic you can CTRL+`Z` to undo. This is a good time to adjust the `DRAW` size to get the right effect for this part of the modelling. Click-Hold away from the head and rotate it slightly. Pull out a neck, back of head, chin and a forehead. (See figure 2. Heads 1 and 2) To add features to this cone-head we need to switch to the `DRAW PONTER` (`Q`). Rotate the head so that it faces you and `paint` depth onto the face. Build up the forehead, the nose, cheeks, lips and ear bumps. Add a bump for each eye for now. To indent the model, still in the same mode, hold down ALT and paint. Indent the cheek recesses, nostrils and the eyeholes. Remember, you may need to reduce the `Z Intensity` in the DRAW panel to make subtle adjustments. Try to follow the steps in Figure 2. Keep rotating and adjusting until you get the desired effect. (See figure 2. Heads 3-8). Add features like frown wrinkles and bags under the eyes. If you need to move the head on the canvas you can exit `EDIT` mode by pressing `T` again. The gyro appears and you can select `MOVE` by pressing `W`. Pull the gyro (grab the coloured ends) and move it in the direction you want. To continue modelling, press `T` and re-enter `EDIT` mode.

To model the ears you can use `SCALE` (E) to enlarge the ear area. Use `DRAW POINTER` to shape the lobe and make an indentation then use `SCALE` (E) to reduce the ear back down to the correct size. This will take some practice as it is not easy the first few times you try it. Make sure you model the `bumps` in the head where the metal hoses will fit.

NOTE: If you select another tool by mistake at this point you will `snapshot` your head into the document - common frustrating mistake. If this happens CTRL+`N` clears the entire layer and you will notice a copy of your head is left in the `TOOL` panel. You can re-select it and `draw` it back into the document and continue to edit it.