Windows 10 / 11 · 64-bit · free
A small Windows modeller for 3D printing: drop in shapes, type exact sizes in
millimetres, cut and combine them, and export a watertight .stl. No cloud, no account,
no installer — one file that opens in a second.
In loving memory of Windows 3D Builder. Rest in peace.
Nine primitives on a 10 mm grid. Type the size you want — not drag it and hope. Subtract, Intersect and Merge run on a hand-written BSP engine that checks its own work: if a result would not be watertight it is refused, and your object is handed back untouched.
Brick, roof tiles, wall tiles, planks, wood grain and stripes — cut in or standing proud, on any flat face, including one that already has windows in it.
Any installed font, or the filled shapes of an SVG. Cut, raised, bevelled, and wrapped round a barrel or a ball.
Weld, cap holes, turn inside-out shells the right way. When that is not enough, Rebuild remakes the surface from scratch and Hollow turns a solid into a shell — with one side left open, if it needs one.
A tape that snaps to corners and edges, either end draggable. Fit check answers the question a render cannot: do these two parts actually meet, and by how much?
Watertightness is checked on every export, and every risky operation says plainly what it did — or refused to do, and why. A modelling tool for printable parts should be hard to leave broken quietly. That is the whole design brief.
Two models built entirely inside the app, by driving its own buttons — then checked by ray-testing the exported STLs against a list of points. 74 checks, all passing.
The ribbon is split by what a tool changes: Object is what a thing is made of, Edit is its surface, Align is where it sits. Nothing is buried in a menu.
§ 03.1
Nine primitives, a stair, and the way in for anything made elsewhere. Every shape lands on the plate at a sensible size and takes its colour from a six-step cycle, so a scene stays legible without anyone painting anything. Import reads STL and OBJ, and another 3DFastCraft project — which joins the plate rather than replacing it.
On the plate: one of each, and a five-riser flight built by the stair tool rather than from a stack of boxes.
§ 03.2
What a thing is made of. Boolean arithmetic on a hand-written BSP engine — Subtract, Intersect, Merge — plus splitting with a plane, duplication beside or in place, repeating along a line, and colour. If a result would not be watertight it is refused and the objects are handed back untouched.
On the plate: a block with a cylinder and a bar overlapping it, all three picked. Subtract turns them into one bracket in a single undo step.
§ 03.3
Where a thing sits, without changing the thing. Drop to the plate, lay a part on a face you pick, mirror it, line a selection up on any axis — flush either side, centred, or spread evenly. Align to centres one object on another; Fit check measures two parts against each other and changes neither.
On the plate: four parts at four different heights, all selected. One click puts their bottoms on Z = 0, another spreads them evenly along X.
§ 03.4
What a thing’s surface is. Emboss lettering or an SVG drawing; engrave brick, roof tiles, wall tiles, planks, wood grain or stripes; smooth and round; and, when something will not print, repair, rebuild, simplify or hollow it.
On the plate: a wall with a window already cut, and the brick drawn on the face as the settings are chosen — the same code that builds the cutter, so what you see is what you get.
§ 03.5
Six axis views and isometric, wireframe, x-ray to see a part buried inside another, the build plate at any size from 20 to 2000 mm, and the tape. Scale 1: changes no geometry at all — it tells you what a millimetre means, so a model reads in metres.
On the plate: the 1:87 house, measured corner to corner. Either end of the tape can be dragged once it is down.
§ 03.6
New, open, recent, save, and named versions kept inside the project file so you can go back to one. Export asks what to write before it writes it: everything or the selection, binary STL, ASCII STL or OBJ, and whether to drop the result to the plate.
On the plate: the same house, exporting one part. The dialog reports the triangle count, the volume, the bounding size and whether the result is watertight — before anything is written, not after.
One self-contained file. No installer, no .NET runtime, no account. Download it, double-click it.
Windows SmartScreen will object the first time — the executable is not code-signed. More info → Run anyway.
SHA-256121bcb92df279265e32e1d1f81b397d1f48e409753bcd22408c36d0b2b3e3897