view3d

A very fast viewer for STL, 3MF and OBJ models, written in Rust.

It is a re-implementation of fstl — the same feature set, camera feel and shading — with two additions: it reads 3MF (including the slicer project files that split objects across model parts) and OBJ, and it renders the colors those formats carry.

Rendering is wgpu; the menus, dialogs and overlays are egui.

Why

Opening a mesh should be instant, even when the mesh is enormous. view3d loads a 2 million triangle binary STL in about 170 ms and then holds a smooth frame rate while you spin it: files are memory-mapped, parsed in parallel, and welded with a parallel sort. There is no scene graph, no import wizard, and no splash screen — you double-click a file and it is on screen.

Draw modes

Shaded	Material Color
The default fstl look: a flat-shaded surface with the normal recovered per-fragment.	3MF color groups and base materials, or OBJ/MTL diffuse colors. Axes shown here too.

Wireframe	Surface Angle
Every edge, deduplicated into a line list.	Face orientation mapped to color — handy for spotting overhangs.

Mesh Light
	Configurable ambient and directional light, with 26 light directions to choose from.

Installing

Arch Linux

Build and install a real pacman package from this checkout:

packaging/arch/install.sh        # runs makepkg --syncdeps --install

Uninstall with sudo pacman -R view3d. packaging/arch/PKGBUILD.aur is the view3d-git template for publishing to the AUR.

Anywhere else

cargo build --release
xdg/install.sh                   # installs to ~/.local, or set PREFIX=/usr/local

Both routes install the binary, icons and desktop entry, and register the model/3mf MIME type. xdg/install.sh also claims the default handler for .stl, .3mf and .obj; after installing the pacman package, do that yourself if you want it:

xdg-mime default view3d.desktop model/stl model/3mf model/obj

Building requires Rust 1.95 or newer.

Using it

view3d model.stl                 # or drop a file on the window

Action	Input
Rotate	Left-drag
Pan	Right-drag
Zoom about cursor	Scroll wheel
Open a file	Ctrl+O, or drop one on the window
Open in another app	Alt+S
Reload	F5
Previous / next file in folder	← / →
Viewpoints	0 iso, 1 top, 2 bottom, 3 front, 4 back, 5 left, 6 right, 9 recenter
Fullscreen	F11
Hide menu bar	Ctrl+Shift+C
Quit	Ctrl+Q

Projection switches between perspective and orthographic, and every view setting persists between runs. Autoreload watches the open file and reloads it when it changes on disk, which makes view3d a live preview to sit beside a CAD tool or slicer.

Rendering a model straight to a PNG, for thumbnails or docs:

view3d model.3mf --screenshot render.png

Format notes

• STL — binary files are memory-mapped and parsed in parallel. Binary versus ASCII is decided by size arithmetic rather than the misleading solid prefix. Magics-style per-facet colors are read when present.
• 3MF — build items, component trees and unit scaling are all honoured, and objects split across model parts by the production extension (p:path) — what Bambu Studio, Orca and PrusaSlicer write — are followed. Colors come from base materials and the materials extension's color groups.
• OBJ — polygons are triangulated and MTL diffuse colors applied. OBJ is conventionally Y-up, so files are rotated to Z-up on import; the View menu can turn that off.

Slicer project files often store their paint colors in vendor-specific metadata rather than standard 3MF color groups. Those models load fine but render in the neutral fallback color in Material Color mode.

Linux backend note

winit implements file drag-and-drop on X11, Windows and macOS, but not on Wayland — under a native Wayland surface the drop events never arrive. view3d therefore asks for the X11 backend by default on Linux (through XWayland in a Wayland session) so that dropping a file on the window works. Set VIEW3D_BACKEND=wayland for a native Wayland window, accepting that drops will not work there; VIEW3D_BACKEND=x11 forces X11.

Development

cargo test                       # loader tests
cargo clippy --all-targets
cargo run --release --example meshinfo -- model.3mf    # headless file check

meshinfo prints triangle and vertex counts, the bounding box, load time and whether the file carried colors — useful for checking a pile of files at once:

find ~/models -iname '*.3mf' -print0 | xargs -0 ./target/release/examples/meshinfo

The loader tests generate a cube in each format at test time — including a 3MF that exercises units, a build transform, a component reference and a color group — and assert that all three describe the same box.

The screenshots above are reproducible:

python3 docs/make-models.py /tmp/view3d-models
python3 docs/make-screenshots.py /tmp/view3d-models docs/screenshots

Layout

Path	What lives there
src/loader/	STL, 3MF and OBJ readers, all producing one Mesh
src/render/	wgpu pipelines and the WGSL shaders
src/camera.rs	Arcball, pan, zoom and the viewpoint presets
src/app.rs	Menus, shortcuts, file watching and overlays
xdg/, packaging/	Desktop integration and the Arch package

License and credit

MIT — see LICENSE.

view3d exists because fstl by Matthew Keeter got the important things right, and parts of it are direct translations of that work rather than merely inspired by it: the fragment shaders, the camera and viewpoint math, and the axis geometry all come from fstl's source. fstl is MIT licensed — it ships no LICENSE file, but its README carries the MIT terms under "Copyright (c) 2014-2017 Matthew Keeter" — and those portions remain under that license. Some of what we ported (the mesh light and surface angle shaders) postdates that copyright line and came from later fstl contributors. See LICENSE for the file-by-file detail.