Base meshes for sculpting

A base mesh is the simple starting shape a sculpt grows from. It sets the proportions and gives the brushes evenly spread polygons to push. A good base mesh saves hours. A poor one, with stretched faces or wrong proportions, causes problems throughout the sculpt.

There are three common ways to make one: draw it with ZSpheres in ZBrush, merge rough blocks with a remesher, or model a low-poly blockout in a modeling package.

#ZSpheres

ZSpheres are ZBrush's tool for building an armature from linked spheres. You drag out a sphere, then add connected spheres to form parent-child chains, where "the initial ZSphere" sits highest in the hierarchy and cannot be deleted (ZBrush for iPad Help: ZSphere Essentials). Move, Rotate and Scale reposition and resize each sphere, and Symmetry mirrors the chain (ZBrush for iPad Help: ZSphere Essentials).

The chain is not yet a mesh. Adaptive Skin turns it into one: Preview shows the geometry, Density sets the subdivision, and Make Adaptive Skin adds the new mesh to the Tool library (ZBrush for iPad Help: ZSphere Essentials). Maxon's guide also suggests choosing the starting sphere with care, because rotation works from it; for a humanoid upper body it suggests the hips (ZBrush for iPad Help: ZSphere Essentials).

ZSpheres are best for branching, tube-like forms: roots, branches, tentacles, creatures and limbs. They are also used for rocks. In his river rock breakdown for The Last of Us Part I, Jared Sobotta shows how he quickly turns a ZSphere into a river rock (ArtStation: River Rock Breakdown).

#Blocks and remeshing

The second route is to throw together rough primitives, overlap them and merge them with a remesher. Maxon describes DynaMesh as redistributing "the model's polygons to be equally sized for a consistent brush stroke on command", and says it can add, merge or "remove geometry in a manner similar to what can be done with Boolean operations" (maxon.net: Base Mesh Creation). Blender's voxel remesh and Nomad's voxel remesher do the same job; see remeshing.

This route suits rocks, cliffs and broken masonry, where exact edge flow does not matter. Sergii Zlobin starts his stone wall from four block meshes of different sizes and proportions (80 Level: Creating a Stone Wall Material in ZBrush…), and JaviSkau blocks out rocks with DynaMesh and ClayTubes (ArtStation: Rock Sculpting Workflow in ZBrush | 3-Step…). Nomad's manual gives the working rhythm: block a rough shape at low resolution and press Remesh "once in a while" when the mesh stretches too much (Nomad Sculpt manual: Topology).

#Modeled blockouts

The third route is to model the base in Blender, Maya or another modeling package, with clean, evenly sized quads, then add subdivision levels in the sculpting tool.

This is the usual choice when the sculpt must fit a grid or a modular kit. Kirill Khafizov blocked out his stylised ruins in Maya or Blender, split the modular pieces from that blockout, and only then moved to ZBrush and DynaMesh (80 Level: How to Make Atmospheric Stylized Modular…). Paweł Kostecki's tomb kit for Indiana Jones and the Great Circle lists Modo and ZBrush together (ArtStation: Indiana Jones and the Great Circle - Tomb Kit), a typical modeling-plus-sculpting mix for kit pieces. See modular kits.

#Common mistakes

• Wrong scale. Build the base mesh at real-world size so brush sizes, bakes and engine imports agree; see units, scale and axes.
• Stretched faces. Long, thin polygons cannot hold detail. Remesh or rebuild before subdividing.
• Too much detail in the base. The base mesh is for proportions. Leave detail for the sculpt.
• Skinning ZSpheres too densely. Adaptive Skin's Density setting controls the subdivision of the new mesh (ZBrush for iPad Help: ZSphere Essentials). Keep it low and add levels later, once the proportions work.

#Related terms

digital sculpting · multiresolution and subdivision levels · remeshing · primary, secondary and tertiary forms · blockout · sculpting rocks and cliffs

#Further reading and watching