Every cut in our library comes as two products: a 3D model in six formats, and a cutting file for the faceting machine. This page is about who uses them, what is in each download, and which programs open every file.
Both are built from the same geometry, so the angles you cut are the angles you render.
Who uses the 3D models
The models are exact faceted gemstones: flat facets, sharp edges and a closed, watertight solid, at real size in millimetres. The girdle is centred on the origin and the table faces up.
Jewellery designers and CAD modellers
Place the stone in a ring, pendant or earring and build the setting around it: the seat, the prongs, the gallery. STEP gives CAD software an exact solid to measure and snap to. 3DM opens directly in Rhino and the jewellery programs built on it.
Jewellery makers and casters
Print the stone in resin to test a setting before any metal is cast, or to check fit and proportion against a wax. STL and OBJ go straight into the slicer.
Renderers and product visualisers
A gem only refracts correctly when its facets are truly flat. Assign a diamond or sapphire material in KeyShot or Blender and the model behaves like a stone, for catalogue images, product pages and animations.
Game developers and real-time 3D
FBX and GLB load into Unity, Unreal Engine and Godot. The meshes are light (the T73 round brilliant is 118 triangles), so a crown full of jewels stays fast.
Web, AR and online shops
GLB is the file for the web. It loads in three.js, Babylon.js and Google’s model-viewer, for product configurators and augmented reality.
Digital artists and hobbyists
Render a stone for the fun of it, animate it, or print it large in clear resin as a display piece. A gem for a miniature, a costume or a school project is a single file away.
Teachers and students
Gemmology and jewellery design are easier to learn from a stone you can turn. Count the facets, measure an angle in FreeCAD, and compare the cut with its entry in the cut library.
Who uses the cutting files
A cutting file is a faceting design: every facet’s angle and index, in cutting order. Each design names its index gear. Most use the common 96-tooth gear, and a few use 64 or 120.
Amateur faceters
Most faceters cut for pleasure, at home or in a club. Print the diagram, fit the gear, and cut tier by tier. Try a new design in inexpensive material, such as quartz, before you cut valuable rough.
Professional gem cutters
Cut rough to a proven design, with the angles taken straight from a checked 3D model rather than copied by hand.
Gem designers
Open the .asc in GemCad or Gem Cut Studio to see how a cut is built. Change the angles for another material, or ray-trace it in GemRay to compare before you commit.
Faceting students
Learn how tiers, meetpoints and cutting order fit together. The tier table lists every step in the order you cut it.
File types and the programs that open them
Every download also includes LICENCE.txt, the licence for the files.
| File | What it is | Opens in |
|---|---|---|
| 3D model | ||
| STEP | Exact faceted solid for CAD | FreeCAD, Rhino, Fusion, SolidWorks, Onshape, KeyShot |
| 3DM | Rhino’s own format | Rhino, MatrixGold, KeyShot |
| STL | Triangle mesh, the standard for 3D printing | PrusaSlicer, Cura, Chitubox, Lychee, FreeCAD, Blender |
| OBJ | Mesh that almost every 3D program reads | Blender, ZBrush, Maya, Cinema 4D, Rhino, FreeCAD |
| FBX | For animation and game engines | Unity, Unreal Engine, Maya, 3ds Max, Blender |
| GLB | glTF in a single file, for the web, AR and real time | Blender, Godot, three.js, Babylon.js, model-viewer |
| Cutting file | ||
| .asc | The GemCad design as text: gear, refractive index, and every facet’s angle and index | GemCad, GemRay, Gem Cut Studio |
| Tier table (.csv) | Angle, index and cutting order for every tier | Excel, Google Sheets, LibreOffice Calc, Numbers |
| Faceting diagram (.html) | Printable diagram of the design | Any web browser. Print it, or save it as a PDF. |
The programs
GemCad
Robert Strickland’s faceting design program for Windows, and the standard format for sharing faceting designs. Open the .asc to see the design, print its diagram, or change the angles for another material.
GemRay
Strickland’s companion ray tracer for Windows. It opens GemCad designs and shows how the finished stone will look, including how it darkens as it tilts, so you can tune the angles before you cut.
Gem Cut Studio
A design and ray-tracing program for Windows and macOS. It opens GemCad .asc files directly, adds tilt-performance, light-path and yield tools, and can export a design as OBJ or STL.
FreeCAD
Free, open-source CAD for Windows, macOS and Linux. It opens STEP as a true solid, using Open CASCADE, the same kernel we use to check every STEP file, so you can measure the stone and design a setting around it. It opens STL and OBJ too.
Rhino
The CAD program behind much of the jewellery industry, for Windows and macOS. It opens 3DM natively, and STEP, STL, OBJ and FBX as well. Jewellery programs such as MatrixGold run inside it.
Blender
Free, open-source 3D for modelling, rendering and animation. It opens GLB, FBX, OBJ and STL.
KeyShot
A renderer widely used for jewellery images. It opens STEP, 3DM, OBJ and FBX.
No software yet? The faceting diagram opens in any browser, and the free 3D Gemstone Simulator shows every cut in the library, in any material, without installing anything.
Personal and professional use
The files are sold with a personal-use licence: for your own projects, stones you cut for yourself and gifts. Selling stones or jewellery, working for clients or using the files in a business needs a commercial licence. Contact us and we will help.