You may notice that the edges on your 3D model (if you are continuing from tutorial 03 – the star) are aliased (jagged).
When you wish to produce a final image in Zbrush, you can anti-alias in various ways.
>> Leave Edit mode by un-toggling Edit button or pressing the shortcut T key.
>> Clear the canvas by pressing Ctrl+N.
>> Go to Document> menu and click Double button.

You will be presented with an alert dialogue.
>> Answer Yes to this.
The document will now be double its’ previous size of 640 x 480.
>> Draw out the previous Polymesh3D Ztool (which should already be selected), onto the large canvas area, and press T key or the Edit button immediately.
The idea behind this process is to create a workspace that is large, draw out the 3D object and half the viewable size to give the effect of anti-aliasing for final images.
>> Now press the AAHalf button on the right of the interface.

Your workspace should now show the Polymesh3D object with anti-aliased (smoother) edges.
The difference is demonstrated in this next image.

A slight problem with this technique for anti-aliasing your image is that your machine has to work with twice the size of image that is actually being shown on your screen. This makes it memory and CPU intensive.

2 Comments
Followed the tuts up to here now zbrush crashes when I click on a tool or item after opening it up.
Now what?
The most likely cause for this is that your model is too complex to for the memory RAM on your machine, or your graphics card may not be up to the task.
Try it with a pre-defined 3D tool from the Palette and this anti-aliasing method should work (plus then you will know that it was the fact that your model was too complex for the machine you’re using).
Hope that solves the issue.