Sculpting for 3D printing
A model that prints has requirements a render never has: one closed watertight surface, no gaps, nothing too thin to survive the build. Sculpt the shape with pressure brushes, give it its real size, run a print check that finds and fixes the problems, hollow it if it is going to resin, and export the STL or 3MF your slicer wants — in a browser tab.
Mold checks each object for holes, non-manifold edges, flipped faces, inside-out shells, self-intersections and walls thinner than your minimum, shows wall thickness as a heat map, and closes holes or remeshes watertight in one click.
Miniatures, busts, creatures, terrain and ornaments are exactly what CAD is bad at. Push, pull and carve the form by eye with clay, crease, pinch and trim brushes instead of fighting a parametric modeler.
Set a wall thickness, add one or two drain holes, and hollow the selected object. Mold reports how much volume that saved — so a solid resin bust stops costing a solid bust's worth of resin.
Give the model its real size in millimetres, centimetres or inches, then export STL or 3MF in millimetres with Z up, the way slicers expect. OBJ and GLB keep your objects separate and named if the model is heading somewhere else first.
Why Mixos
Three things, and they are easy to satisfy if you know them in advance and painful to retrofit if you do not. The first is that the mesh must be watertight — one closed surface with no holes, no gaps and no faces that pass through themselves. A slicer works by asking whether a given point is inside or outside the model, and an open mesh makes that question meaningless. This is the single most common cause of a failed print, and a voxel remesh solves it in one operation by rebuilding the sculpt as a continuous shell.
The second is detail scale. Fine work below roughly 0.4 mm at final size will not resolve on a filament printer no matter how good it looks on screen, so pores and fine scratches are wasted effort unless you are printing in resin — which is exactly why tabletop miniatures are resin-printed. Sculpt detail at the size it will actually be seen.
The third is fragility. Thin projections — a sword blade, a whisker, an outstretched finger, an antenna — will snap in your hand even when they print successfully. If something looks delicate on screen it is too delicate in plastic, so thicken it before exporting, however wrong that looks in the render. Overhangs and undercuts need support material or they will fail mid-print.
The workflow that follows is short. Sculpt the form and the detail first and ignore print preparation entirely while you work — it is a finishing step, not a constraint to sculpt under. Then open the 3D print panel: set the real size, run the check, close holes or remesh watertight where it finds problems, use the thickness map to find anything thinner than about 2 mm and build it up, hollow it if it is going to resin, and export STL or 3MF. Sculpting, checking, hollowing and decimating are all free; downloading the file is what a paid plan covers, so you can take a model to print-ready before deciding.
For organic subjects — miniatures, busts, creatures, terrain — a sculpting tool beats CAD, because you are judging shape by eye rather than by measurement. Blender and ZBrush are the established desktop options. Mold runs in a browser with no install, sculpts with pressure brushes, checks and hollows the mesh for printing, and exports STL or 3MF. For mechanical parts with real tolerances, use a parametric CAD tool instead — that is not what sculpting is for.
Run the print check first: it counts holes, non-manifold edges and inside-out shells, and Close holes fixes simple gaps in one click. For anything tangled, a voxel remesh discards the existing topology and rebuilds the surface as a single closed shell — exactly the manifold geometry a slicer needs. Do that after the form is finished, since a remesh also resets your subdivision levels.
As a rule of thumb, nothing below about 2 mm at final scale on a filament printer, and detail below roughly 0.4 mm will not resolve at all. Resin printers hold much finer detail, which is why miniatures are printed on them. If a part looks fragile on screen it will break in your hand — thicken it before exporting.
Yes. Mold exports STL and 3MF in millimetres with Z up, plus OBJ, GLB and FBX. STL fuses every visible object into one solid, which is what a slicer expects — hiding an object is how you leave it out of the export. Export is part of a paid plan; sculpting, checking, hollowing and decimating are free.
Probably, and it rarely matters visually. Slicers slow down badly on multi-million-triangle meshes while the print itself resolves far less detail than that. Decimate before exporting — it keeps the silhouette and holds density where curvature is high, which is all the printer can reproduce anyway.
Yes. Set a wall thickness in millimetres, choose no drain, one or two and their diameter, and hollow the selected object — Mold reports the volume saved. Run the wall-thickness map afterwards so nothing came out thinner than your printer can hold.
Keep exploring
3D sculpting software
Sculpting for beginners
ZBrush alternative
Sculpting on iPad
