Core Workflow: Creating Vertices
The foundation of your retopology starts with placing individual vertices (points) on your model's surface. These vertices are the building blocks of your new topology.
- With the Retopo brush selected, click on your model's surface to place vertices (dots).
- Continue clicking to add more vertices where you want your topology to flow.
- Press the spacebar to establish a temporary blue polygon within the vertices around your pointer, then click your mouse to confirm and generate that polygon (displayed as red). Shown here is a confirmed polygon on the left and a polygon preview being shown (in blue) while the spacebar is pressed.
What this does:
Each click places a vertex that snaps to the surface of your reference model. These vertices "float" on the surface until you confirm them, at which point ZBrush connects them into polygons based on their proximity.
Why you'd use this:
Vertex-by-vertex placement gives you absolute control over polygon flow. This is essential when creating topology for specific purposes, such as edgeloops around facial features, where precise polygon direction determines how well the mesh deforms during animation.
Note that you can easily create multiple edges within a polygon by using the spacebar with your mouse dragging. To do this, begin with your mouse on the edge of the polygon you wish to divide. Hold down the spacebar, hold down the mouse button, and then drag the mouse to create the two new vertex points and their connecting edge shown below (left). While the green line is visible, release the spacebar but keep the left mouse button held down. Now drag the mouse back and forth to create additional vertices and edges (right).
Understanding brush size and vertex selection
Brush size matters: When pressing spacebar to confirm polygons, only vertices within the brush radius (shown as a red circle) connect. Adjust your Draw Size to control how many vertices are included in each polygon creation. A smaller draw size is useful for precise, local adjustments to specific areas. Larger draw sizes can help with confirming or moving larger retopology areas at once.
In the above image, we show how Draw Size radius impacts selection of vertices. On the left, only two vertices fall within our brush radius. Since it takes at least three points to form a polygon, nothing happens when we select spacebar. When we scoot the brush over to cover three vertices (center), a triangle becomes possible. With four vertices within the radius (right), a quadrilateral emerges. If the Draw Size is too small, you may not be able to encompass all desired points. Similarly, a too-large radius may capture too many.
The same principle applies with capturing vertices and dragging them to change polygon shapes. A Draw Size of 1 lets you grab a vertex point for dragging but nothing more. Larger brush sizes can capture more points at once.
Dual brush sizes
The Retopo brush uses two independent brush sizes that operate in tandem, one for "normal" operations and the other for when you press the spacebar. This dual system prevents you from constantly adjusting brush size as you switch between different tasks. For example, you might choose to use your "regular" Retopo brush (spacebar released) for controlling vertex movement and selection while repositioning topology, then use a different-sized brush (with spacebar depressed) for creating polygons between vertices.
In the example above, we show Draw Size settings of 30 (left) and 150 (right). Toggling between these is simply a matter of pressing the spacebar. To adjust these "with" and "without" spacebar modes, either do or don't depress the spacebar while adjusting the Draw Size parameter (either via keyboard input or by click-dragging your mouse laterally over the Draw Size field). You can visually distinguish the modes by whether the little, white polygon appears near your cursor when the spacebar is depressed, as shown above.