Simply3D

Simple, fast 3D modelling for 3D printing.

Simply3D is a free remake of Microsoft 3D Builder, written in Rust. It keeps 3D Builder's simple tab-and-ribbon way of working and adds the precision, repair, painting and sculpting tools 3D Builder never had. It's one portable program for Windows and Linux: nothing to install, and it handles models with millions of triangles.

Download

Get it from the Releases page.

Windows: download Simply3D-windows-x64.zip, unzip it and run simply3d.exe. It works on 64-bit Windows 10 and 11 with DirectX 12 or Vulkan.

Linux: download Simply3D-linux-x64.tar.gz, then:

tar xzf Simply3D-linux-x64.tar.gz
cd Simply3D
./simply3d          # run it straight away, or
./install.sh        # add it to your applications menu (no root needed; ./install.sh --uninstall removes it)

It runs on 64-bit distros from 2022 on (Ubuntu 22.04+, Debian 12+, Fedora 36+, Mint 21+, Arch and others), on Wayland or X11, and needs a Vulkan graphics driver (see the notes under Build from source).

Open models from the ☰ menu, drag files onto the window, or pass them on the command line: simply3d part.stl project.3mf.

Features

Files

• Open: STL (text and binary), OBJ with MTL colours, PLY, 3MF, and pictures (PNG, JPG, BMP, TGA, GIF, WebP).
• Save and export: 3MF projects, STL, OBJ and PLY, or just the selected objects.
• Print (Ctrl+P): one window that checks the plate before you print (parts off or below the plate, too big for the printer, open meshes, overhangs that need supports, thin walls), with a one-click fix for each, then opens the plate in your slicer. It finds Bambu Studio, OrcaSlicer, ElegooSlicer, PrusaSlicer, UltiMaker Cura, Creality Print and others, or uses the app your computer opens 3MF files with.
• Slicer projects: reads and writes Bambu Studio, OrcaSlicer and PrusaSlicer 3MF files, keeping objects, parts, colours, painted areas and negative parts.
• 3MF files carry a thumbnail, so Windows Explorer and slicers show a preview.
• Recent files, autosave and crash recovery.

Shapes and generators

• Basic shapes: cube, cylinder, cone, sphere, torus, tube, pyramid and wedge. Cubes and cylinders take exact rounded or chamfered edges.
• Sketch (K): draw rectangles (with rounded corners or as slots), circles, polygons and outlines with straight and curved segments on the plate or on any face, with grid snapping, snapping to corners and centres, and exact sizes in the bar. Shapes drawn inside another become holes; overlapping shapes merge. Then extrude them into a new part, onto the object you drew on, or cut them into it (also all the way through), or revolve them into an upright part (vases, knobs, wheels), all with a live 3D preview.
• Text: any installed font, several lines, with height, depth, spacing and alignment. Place it on the plate, or emboss or engrave it onto any face, wrapping around curved surfaces.
• Pictures to 3D: outline, height map, edge, stamp or lithophane. Place a picture on the plate, or emboss or engrave it onto a face.
• Threads: bolts, nuts, threaded rods, tubes and tapped holes. Pick a standard size (metric M2–M24 or UNC #4–1/2") or make your own: any diameter and pitch; V, trapezoidal, square, buttress, rounded, or a printable 45° profile that needs no supports either way up; custom depth; multi-start; left- or right-hand. Bolts get hex, socket, countersunk, round or knurled heads and an optional plain shank; nuts can be hex, square, round or knurled, with a closed top for caps. A clearance setting makes printed parts screw together.
• Screw-on lids: a jar lid and matching threaded neck, ready to customise.
• Mechanical parts: involute gears, compression springs, print-in-place hinges and snap-fit clips.
• Boxes with lids: snap, slide or hinged lids, with dividers and a fit clearance.
• Modular storage: grid-based storage bins, with an optional stacking lip, compartments and magnet pockets, plus matching baseplates.
• Building bricks: studded bricks, plates and smooth tiles in two sizes, with fit settings so printed parts click together.
• Click to place: new shapes follow the pointer and stand on whatever face you click, or press C (or Plate centre) to drop them in the middle of the plate. Settings can make every new shape go straight to the centre or beside the others.
• Edit them later: select a generated part (gear, bolt, box, bin, brick…) and change its settings in the side panel; it rebuilds in place. The settings are saved in your 3MF projects.

Arrange and edit

• Move, rotate and scale with the mouse or the gizmo, with snapping to grid steps and to other objects (guides show what lines up).
• Exact values everywhere: position, size in mm (with locked proportions), scale %, rotation. Number fields accept maths and units (20+5, 1in, *2, 50%).
• Type a distance while dragging for an exact move, or nudge with the arrow keys.
• Align, distribute, mirror, lay flat on a face, drop to plate, centre on plate, and bake rotation and scale into the shape.
• Arrays: grid copies, or circular copies around a centre (spokes, bolt circles, petals), with an outline of where each copy will go before you create them.
• Auto-arrange packs parts on the plate; auto-orient turns parts for the least overhang.
• Groups, hide, isolate and lock. Unlimited undo and redo.

Combine and cut

• Merge, subtract and intersect with a robust boolean engine that runs in the background.
• Holes: turn any object into a hole that cuts live as you move it. Save it as a negative part for the slicer or as a finished cut.
• Cut with a plane, with optional pegs or dowels so the halves fit back together.
• Split to fit the printer: a model too big for your printer is cut into pieces that fit (turned if that saves pieces), with pegs or dowels, and laid out ready to print.
• Combine objects into one without a boolean, separate an object into its loose parts, or separate selected faces.

Mesh tools

• Analysis and repair: finds open edges, holes, non-manifold edges, flipped faces and loose parts, and fixes them in one click. Shows volume and surface area.
• Make solid: rebuilds a broken scan or messy mesh as one clean closed solid, or thickens open surfaces into a shell.
• Simplify to fewer triangles while keeping the shape and sharp edges.
• Smooth: subdivide, relax or refine, with sharp edges kept.
• Round edges: fillets on any closed mesh, outside, inside or both.
• Hollow with a wall thickness and drain holes.
• Extrude down to the plate, for flat bases and simple supports, threaded parts included.
• Face tools: select an area and extrude it, flatten it, smooth it, paint it, copy it as a solid, delete it, or lay the model flat on it.
• Patterns: Voronoi cells, wireframe struts and gyroid lattices.
• Textures: knurl, ribs, bumps, grid, bricks, carbon fibre, wood grain, leather, waves, sand, or your own picture, pressed into the surface as real geometry.

Paint and sculpt

• Paint colours onto models for multi-material printing, with a brush, fill or single triangles and an eraser. Paint survives booleans, repairs and mesh tools, and is saved in Bambu, Orca and Prusa formats.
• Sculpt with draw, inflate, smooth, flatten and grab brushes, with mirroring and automatic detail under the brush.

View and measure

• Perspective or orthographic view, view presets, and a clickable axis indicator.
• Smooth shading, wireframe, section view and X-ray. Open or inside-out surfaces show in red.
• Print check: colours overhangs, thin walls and islands (spots that start in mid-air) so you can fix or support them before slicing. Set the overhang angle and the thinnest wall for your nozzle.
• Printer presets (Bambu Lab, Elegoo, Prusa, Creality, Anycubic and more) set the plate size and build height, with warnings for parts off or below the plate.
• Measure distances, angles, the gap between faces, and hole or pin diameters. Scale a model to a measured size, or add a tube or channel between two points.
• Stays responsive on multi-million-triangle models.

Comfort

• 3D Builder-style ribbon with Insert, Object, Edit, Surface, View and Help tabs.
• One place for everything: the ribbon holds the actions, the bar under the view holds the settings of whatever you're doing (with a live preview), and the side panel shows what's selected: its settings, position and size, and its health.
• Command search (Ctrl+K) finds any action by name.
• Notices tell you what just happened, with Undo right there. Right-click menus, progress bars with cancel, and preview before applying.
• Dark and light themes.
• Update check: once a day at start-up Simply3D asks GitHub for the latest release and shows a button when a new version is out (turn it off in Settings; nothing else is sent). Help → Updates checks right away.

Keyboard and mouse

Input	Action
Left-drag on an object	Move it (Alt: up/down, Shift: lock axis)
Left-drag on empty space	Orbit
Shift + left-drag	Box select
Right or middle drag	Pan
Wheel	Zoom toward the cursor
Double-click	Set the orbit centre
W / E / R	Move / rotate / scale
M / L / T / P / S / B	Measure / lay flat / text / paint / select faces / sculpt
A	Auto-arrange
D	Drop to plate
F / Home	Frame the selection / everything
1 / 3 / 7 / 0	Front / right / top / iso view
O	Orthographic on or off
X	Section view
Shift+S / Shift+W	Smooth shading / wireframe
H / Shift+H / I	Hide / show all / isolate
Ctrl+G / Ctrl+Shift+G	Group / ungroup
Ctrl+L	Lock
Ctrl+P	Print: check the plate, open it in your slicer
Arrows, Page Up/Down	Nudge (Shift ×10, Alt ×0.1)
Type a number while dragging	Exact move (25, 10,5, 1,2,3)
Ctrl+Z / Ctrl+Y	Undo / redo
Ctrl+D / Del / Ctrl+A	Duplicate / delete / select all
Ctrl+N / Ctrl+O / Ctrl+S	New / open / save
Ctrl+K	Command search
Esc	Cancel, leave the tool, clear the selection

Build from source

Windows

1. Install Rust from https://rustup.rs.
2. Run build.bat, or:

cargo build --release
target\release\simply3d.exe

Linux

To build it yourself instead of using the download:

1. Install Rust:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source ~/.cargo/env

2. Install the build tools and window-system libraries:

# Debian / Ubuntu / Mint
sudo apt install build-essential git libxkbcommon-dev libwayland-dev libx11-dev libxcursor-dev libxi-dev libxrandr-dev mesa-vulkan-drivers

# Fedora
sudo dnf install gcc git libxkbcommon-devel wayland-devel libX11-devel libXcursor-devel libXi-devel libXrandr-devel mesa-vulkan-drivers

# Arch (pick the Vulkan driver for your GPU: vulkan-radeon, vulkan-intel or nvidia-utils)
sudo pacman -S base-devel git libxkbcommon wayland libx11 libxcursor libxi libxrandr vulkan-icd-loader vulkan-radeon

3. Build and run:

git clone https://github.com/p3tr0s/Simply3D.git
cd Simply3D
./build.sh                           # builds, then runs it; or: cargo build --release
./target/release/simply3d model.stl  # run it again later

To update later: git pull, then ./build.sh again.

Notes for Linux:

• Simply3D draws with Vulkan, so it needs a working Vulkan driver (vulkaninfo from vulkan-tools checks it). Without a GPU driver, Mesa's software Vulkan (lavapipe) works, but slowly.
• It runs on both Wayland and X11.
• Open and Save use your desktop's file picker through xdg-desktop-portal. GNOME, KDE and most desktops have it; on a bare window manager, install xdg-desktop-portal plus xdg-desktop-portal-gtk or -kde.

Releases

Releases publish themselves: change version in the top-level Cargo.toml, add the notes as release-notes/vX.Y.Z.txt, and push. Once the Windows and Linux builds pass, GitHub Actions creates the vX.Y.Z tag and the release with both downloads.

Tests and layout

cargo test --workspace runs the tests. The code is split into s3d-core (geometry, file formats, booleans, repair; no UI) and s3d-app (the egui + wgpu desktop app).

License

Simply3D is free software under the GNU General Public License v3.0 or later. Icons are from Lucide (ISC). Booleans use boolmesh (MPL-2.0).

Microsoft 3D Builder is a trademark of Microsoft. Simply3D is an independent project and isn't affiliated with or endorsed by Microsoft. Other names may be trademarks of their owners.