The Retopo brush provides a comprehensive toolset for creating clean, animation-ready topology over your high-resolution sculpts. Unlike automated tools such as ZRemesher, the Retopo brush gives you complete artistic control to place vertices, edges, and polygons exactly where you need them. This level of control is particularly important for creating proper edge loops around areas that deform during animation, such as eyes, mouths, and joints — areas where automated tools may not produce the specific topology flow your project demands.
Topology refers to the pattern of polygons that make up a mesh. While high-resolution sculpts are ideal for creating detailed forms, they're often too dense for efficient animation and deformation. A sculpted head might contain 100,000 polygons or more, but for animation, you typically need a much cleaner mesh with 10,000-20,000 polygons arranged in specific patterns.
What retopology does: Retopology is the process of creating a new, lower-polygon mesh over your more detailed model. This low-poly mesh "wraps" around the underlying form's shape, thus providing cleaner edge flow optimized for animation rigs and deformation.
Why manual retopology matters: While ZRemesher excels at automatic retopology, there are times when you need precise control. Animation-ready characters require specific edge loop patterns around facial features and joints that automated tools may not produce consistently. For example, you need edge loops that encircle the eye socket and mouth to allow for proper facial expressions. The Retopo brush lets you define these critical topology patterns yourself, ensuring your mesh deforms exactly as intended when rigged and animated.
The minimum hardware requirements for ZBrush for iPad photogrammetry are:
iPadOS 17 (or later)
A14 Bionic chip (or later)
LiDAR scanner (for full capture mode)
Find the Retopo brush in the Brush palette. When you select it and top on your model's surface for the first time, ZBrush prompts you to create a new subtool for your retopology mesh. This automatically separates your reference model from the new topology you're creating.
The Retopo brush works on your existing model as a reference surface. When you first place a vertex, ZBrush displays a dialog (shown above) asking if you want to create a new subtool. Select Yes to create a separate retopology mesh. This new subtool is inserted into your SubTool list (not appended to the end), placing it directly above your reference mesh for easy access. Clicking No allows you to edit the currently selected subtool. It's best to create a copy of this mesh as another subtool so the brush can have the copied mesh to edit the topology.
When you activate the Retopo brush, ZBrush automatically enables Polyframe so you can see your topology structure clearly, with visible edges and vertex points.
The Retopo brush uses a 3D projection system that can project vertices even to points not visible from the current camera angle. This means you can create topology that wraps around your model without constantly rotating your view to reach hidden surfaces.
The Retopo brush consolidates retopology functions into a single, streamlined brush interface that proves particularly powerful here in the ZBrush for iPad version.
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.
Hold the spacebar on the Modifier Wheel to establish a polygon within the vertices around your pointer, then tap to confirm and generate that polygon. Shown here is a confirmed polygon on the left (in red) and a polygon preview being shown (in blue) when the spacebar is depressed.
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 while dragging. To do this, begin with your finger/pen on the edge of the polygon you wish to divide. Hold down the spacebar and drag to create the two new vertex points and their connecting edge shown below (below, left). While the green line is visible, release the spacebar but keep your pointer contact pressed down. Now drag with your pointer back and forth to create additional vertices and edges (right).
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.
The Retopo brush uses two independent brush sizes that operate in tandem, one for "normal" operations and one "Dynamic Mode" for when you depress 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 (with 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 the Draw Size settings for regular and Dynamic modes. Toggling between these is simply a matter of pressing the circled "D" symbol.
Once you have initial polygons, you can grow your mesh organically by extruding edges. Edge extrusion creates new polygons by extending existing edges outward, automatically placing new vertices on your reference surface. This is one of the fastest ways to build topology.
How to do it:
You're likely already familiar with the process of dragging a vertex point (below, left) or a polygon edge (right) and how this will skew your near-proximity polygons.
Edge extrusion adds new retopo geometry onto the current polygons.
Hold Alt and click-drag from an edge to extend it (shown below). Releasing the mouse button confirms the new polygon.
While still dragging with Alt+dragging with the mouse button held down, tap Alt again to toggle between two additional extrusion modes.
Edgeloop extrusion: Extends only the selected side, a matched number of new polygons.
Polyloop extrusion: Extends the entire loop of connected edges. Again, note how all of this additional geometry is created by simply dragging a single polygon edge (circled below).
Why you'd use this:
This toggle gives you precise control over whether you're building topology locally (for detail areas) or extending entire sections (for broad coverage). The ability to switch modes mid-stroke without releasing your pen makes for an extremely fluid workflow. For example, you might start extruding a single edge around a nostril, then tap Alt to switch to loop extrusion mode to quickly build out the rest of the nose area.
After creating topology, you'll likely reposition vertices and edges to refine polygon flow and ensure proper alignment with your reference model's features.
To reposition your topology:
Moving vertices: Click and drag vertices to new positions. Brush size determines how many vertices move together.
Moving edges: Click and drag edges to adjust polygon flow.
Moving faces: Click and drag polygon faces to alter a given polygon and the polygons near it.
Why you'd use this:
Topology rarely comes out perfect on the first pass. Moving vertices allows you to adjust edge flow to follow muscle structure, anatomical landmarks, or surface contours. The Alt-toggle is particularly useful when you realize mid-adjustment that you need to move an entire loop rather than a single point. You can simply switch modes without starting over.
To remove unwanted geometry:
Delete polygons: Alt+click on a polygon.
Delete vertices: Alt+click on a vertex.
ZBrush offers yet another means of growing topology, this time by manipulating individual vertices. In the following example, a basic retopo mesh sits on the model. Say you want to extend that retopo mesh upward. In the following example, you would place your pointer on the desired vertex, press down Alt, then drag upward. Release the mouse button to create a quad. As the video shows, you can repeat this process.
If you release the Alt key before releasing the mouse button, then your quad splits into two triangles. However, when you repeat the process in an adjacent extrusion the left half forms a quad with the adjacent polygon while the right remains a triangle.
Vertices and edges automatically merge when moved close together, welding separate topology sections into a continuous mesh. The same process applies when dragging edges.
Why you'd use this:
This is useful for connecting separate topology sections you've built independently or for cleaning up overlapping geometry. Simply drag a vertex near another vertex (or an edge to another edge), and they will snap together when sufficiently close. This automatic snapping behavior means you don't need to manually weld points. ZBrush handles the connection for you.
What this does:
For faster topology creation over larger areas, you can draw curves that generate polygonal strips.
Why you'd use this:
Curves excel at creating clean topology strips across smooth surfaces like foreheads, cheeks, or limbs. Rather than placing dozens of vertices manually, you can draw two parallel curves and generate an entire strip of polygons in seconds. This method is significantly faster than placing vertices individually when you need to cover broad, continuous surfaces.
Curve workflow:
Hold Alt and drag across the surface. This draws a green line segment with green vertices at each end.
Click and hold on the line, then drag back and forth to generate vertices within the segment. Doing so causes the line to conform (curve) to the underlying topology.
Draw another curve line parallel to the first. It automatically replicates the number of vertices in your first line and similarly curves to your topology.
Release the mouse button and ZBrush automatically creates polygons between your lines (shown below). Click on the surface to confirm and generate a mesh strip.
Need more than a strip? Keep drawing additional lines.
Before confirming the mesh strip, you can left-click on an edge line or an edgeloop within the strip and drag to add (or subtract) vertex subdivisions. This increases/decreases the number of edgeloops across the resulting geometry and provides an easy way to change your edgeloop count after initial mesh creation rather than recreating the mesh from scratch. For situations when you need to expand your mesh density, as when you need a retopo mesh to conform to the underlying model curvature, this approach is a huge time-saver.
Take a look at this in practice:
As covered earlier, you begin by Alt-dragging a curved line of vertices (above, left). Add a second, matching line (center), then release the mouse button to establish edgeloops between the lines (right).
Next, hold down Alt and press-drag an edge line to increase your retopo mesh's number of edgeloops (see below).
Repeat the process with the top or bottom edge to add edgeloops in the other direction.
And keep in mind that you can even add edgeloops within prior edgeloops, as shown here:
The Retopo brush includes over 200 pre-made topology patches accessible through the IMM Viewer tabs at the top of the screen. These patches provide instant starting points for common shapes, from simple squares to complex hexagonal patterns.
Why you'd use this:
Patches accelerate topology creation for common shapes. Rather than manually placing vertices to create a grid, you can stamp down a pre-made patch and adjust it to fit. This is particularly useful for starting large areas like torsos or establishing cylindrical forms around limbs. See below how we dropped an "eye patch" onto a mesh. Now imagine the time savings of this one-step operation versus creating fine tuning that retopology from scratch.
Select a patch from the IMM Viewer.
Place a vertex on your model surface. This becomes the patch center point.
Hold Alt and drag to place and scale the patch.
Before confirming, you can:
Drag to adjust size and position. We show this in the image below. Note how the manipulator icon changes to the patch symbol.
Swap between similar patches by selecting different patches from the IMM Viewer, like so:
Press Alt to display green borders for free-form shape editing.
Click on the surface to confirm the patch.
Patch density visualization: The orange wireframe overlay shows the actual polygon structure of the selected patch. Denser patches (like a 6×6 grid) have more subdivisions, giving you finer control in specific areas. Less dense patches (2×2) are better for broad coverage.
When green borders appear (after pressing Alt while a patch is active), you enter free-form editing mode. In this mode, you can click and drag the patch boundary vertices to conform to your model's surface contours or design needs.
In this example, we start with a simple 3x3 grid (left) with eight total edge vertices. By pressing Alt to enter the free-form editing mode, we drag laterally along the top and side edges to create the additional vertices you see here:
Use these additional vertices to refine and reshape your new patch mesh as you see fit.
Free-form patch editing is particularly useful for wrapping patches around curved surfaces or conforming rectangular patches to organic forms. For example, you might place a square patch on a cylindrical arm, then use free-form editing to bend the patch to follow the arm's curvature.
If you place multiple patches that overlap, ZBrush generates the geometry for each patch independently. The patches will overlay each other without creating conflicts or merged vertices. This behavior is similar to applying real fabric patches that stack atop each other.
Start with major forms: Block out large areas first using curves or patches, then refine with individual vertex placement. This top-down approach is faster than building entirely from individual vertices.
Mind your edgeloops: For characters, ensure edgeloops flow around eyes, mouths, and other areas that will animate. Loops should follow natural muscle and bone structure. Edgeloops perpendicular to bending axes (like around a knee) allow for smooth deformation.
Check your work in stages: Regularly hide your reference model (click the eye icon in the SubTool palette) to see only your retopology mesh. This helps identify problem areas in your polygon flow, such as triangles in areas that should be quads, or edge loops that don't flow smoothly.
Use symmetry when appropriate: Enable Transform > Symmetry before starting retopology on symmetrical subjects to work more efficiently. ZBrush will mirror your vertex placement and topology creation across the symmetry axis.
Keep it low-poly: Remember that retopology's goal is to create a cleaner, lower-polygon mesh. Don't add more polygons than necessary for your target application (game engine, animation rig, etc.). A common mistake is creating retopology that's still too dense to be useful.
Project details later: Focus on getting clean topology flow first. You can transfer sculpting details to your retopology mesh afterward using the Projection features in the SubTool palette. This separation allows you to prioritize topology structure without worrying about losing surface detail.