Preview any
3D model.
Preview3D is a fast, native macOS viewer for STEP, STL, OBJ, glTF, 3MF and more - with Quick Look thumbnails, painted multi-material 3MF, PMI/GD&T inspection, and one-click conversion to STL / OBJ / GLB / USDZ.
$9 · one-time · macOS 14 Sonoma or later
Flange model · KittyCAD
From CAD to mesh to print - all in one window.
Built for engineers, makers and 3D printing.
A focused viewer that does the slow, painful parts well - CAD tessellation, Finder previews, and conversion - without the bloat.
Native & fast
A real macOS app built on SceneKit / Metal - models load and orbit instantly, with a clean, consistent presentation look.
Real STEP supportbeta
Reads STEP / STP via StepKit, a pure-Swift B-rep kernel - watertight tessellation with crease-aware normals, straight from the exact geometry, and per-part STEP colors. In beta: most files render great, some complex geometry is still being refined.
Quick Look & thumbnails
Spacebar-preview and Finder thumbnails for every supported format - including STEP, painted 3MF, FBX and 3DS that macOS can't render on its own.
Painted multi-material 3MF
Renders PrusaSlicer multi-material painting (mmu_segmentation) in its filament colors - including fine sub-facet brush detail.
Inspect & measure
An info panel with volume, surface area, centre of mass, watertightness, dimensions and B-rep structure - plus an instanced assembly tree, where clicking a sub-part highlights and isolates it.
PMI & GD&T
Read the manufacturing intent in a STEP file (AP242): dimensions with ± tolerances, geometric tolerances and datums - listed in the panel, with the graphical annotations drawn over the model.
One-click convert
Turn STEP into STL / OBJ / GLB / USDZ, or any loaded scene into STL / OBJ / PLY - whole model or a single selected sub-part.
Snapshots & export
Save a PNG of the current view at 1×, 2× or 4× - for docs, listings, or print-prep - with the same look you see on screen.
Painted prints, in full color.
PrusaSlicer stores multi-material painting as per-triangle segmentation that nothing else on macOS can preview. Preview3D decodes it - palette and all - so you see the finished multi-color print before it leaves the slicer.
- Reads
mmu_segmentation+ the filament palette - Sub-facet brush detail, not just per-face color
- Works in the window, Quick Look and thumbnails
Convert, don't re-export.
Open a STEP from a vendor, export it as STL for the slicer, GLB for the web or USDZ for AR - without round-tripping through heavyweight CAD. STEP conversions use Preview3D's exact B-rep tessellation; everything else goes through Apple's Model I/O.
- STEP → STL / OBJ / GLB / USDZ
- Any scene → STL / OBJ / PLY
- Watertight, high-quality meshes
Strap-hinge model · KittyCAD
One app. One price.
A native macOS app on the Mac App Store. No subscription.
Mac App Store · macOS 14 Sonoma or later · Apple silicon.
- STEP, STL, OBJ, PLY, glTF/GLB, DAE, 3MF & more
- Quick Look previews & Finder thumbnails
- Painted multi-material 3MF in full color
- PMI / GD&T inspection (AP242)
- One-click convert to STL / OBJ / GLB / USDZ / PLY
- PNG snapshots at 1× / 2× / 4×
- Free updates