ZBrush - Dynamesh and Masking

A perfecly normal sphere, with Polyframes (Shift F) turned on to show the polygonal geometry

Whilst sculpting in ZBrush is very easy to get the hang of, often you will run into a snag where you have stretched the polygons too far and they will become jagged and lower in resolution.

Jagged edges have formed because the resolution is too low

Above is an example of where the surface of the model has been pulled out too far and the resolution on the part that has been pulled out has decreased. However, there is a solution that will rectify this problem and allow for a more seamless sculpt.

The DynaMesh sub-menu can be located in the Geometry menu

DynaMesh works by creating equally spaced lines both vertically and horizontally across the model. Where these lines intersect with the model, a point will be created so that it forms into an evenly spaced model that is ready to be sculpted upon. As shown above, there are many options, however you should only really need to look at the DynaMesh button and the resolution. Changing the resolution changes how much the mesh gets divided, introducing more points than it would at a lower resolution.

The mesh has been DynaMeshed

You can activate DynaMesh by either pressing the button or, whilst sculpting with the DynaMesh button already pressed, by dragging a mask outside of the model. However, there are many drawbacks to using DynaMesh. DynaMesh does not consider topology so every area will be as detailed as everywhere else. There is also the issue that finely sculpted features will be blocky unless you increase the resolution.

When the masking tool (Ctrl) is selected, the cursor will turn yellow

Masking (with the Ctrl key) can also be used to obscure parts of the model from editing. This will affect tools like DynaMesh as well as regular sculpting. There are many different things that can be done with the Mask tool:

• When you are hovered over the mesh, the Masking tool will default to a pen, allowing you to draw on the mask.
•  If you start creating a mask from outside the selection of the mesh, you will default to a rectangular mask.
• Dragging a mask outside the mesh while there is a mask applied will clear the mask. 
• Clicking outside the mesh will invert the mask.
• Clicking on the mesh will soften the mask.
• Clicking on the mesh whilst subtracting (hold the Alt key) will sharpen the mask.

The darkened area of the mesh is where the mask is

Keep in mind that masked areas will not be affected by any tool, including even subdividing, so make sure to subdivide your mesh before you mask or you will end up with a very un-even resolution, unless that is your intention!