Getting the diamonds in: STL, STEP and 3DM, step by step

First, which file do you have?

Three cases, and the rest of this article is one section each. If you can choose, the order of preference is STEP with named bodies, then STL plus the 3DM, then STL alone.

• STEP (.stp/.step): each body is a separate part with a name. Load it and the studio finds the stones by name, size and shape — nothing else to do unless a name is wrong. Section 4.
• STL plus the design's 3DM: the STL is the metal, the 3DM places the stones exactly, in one click. Sections 2 and 3.
• STL alone: export it in parts so the stones survive, or place them by hand. Section 2, then the guide on adding stones to an STL.

Export an STL in parts from Rhino or MatrixGold

An STL has no parts of its own — it is one list of triangles — but the studio splits it wherever the geometry is disconnected. So 'in parts' means: export everything in one file, and make sure the pieces do not touch. A stone that sits in its seat without touching the prongs comes out as its own part; a band, head and prongs that are one solid come out as one part, which is what you want. The short version for Rhino is below; the export guide covers MatrixGold, SolidWorks and Fusion as well.

1. In Rhino or MatrixGold, turn on the layers that hold the metal AND the stones. Hidden layers are not exported.
2. Select the metal bodies and every stone you want in the render. Gems that are block instances export fine — the exporter writes their geometry.
3. Check that no stone is unioned with the metal. If a stone was Boolean-joined to its prongs it is one shell with them and cannot be separated afterwards; undo that, or keep the stone as a separate object.
4. File → Export Selected, choose STL, and in the mesh settings pick a fine setting — smooth, slow, or a small maximum edge length. A coarse STL shows facets on the band that no material can hide.
5. Choose binary STL. It is a fifth the size of ASCII and loads faster; nothing is lost.
6. Drop the STL into the studio. Watch the Auto setup toast: 'N stones + M metal parts'. If it says 0 stones and 1 metal part and the ring has stones, they touched the metal and welded into it — go to the next section and use the 3DM instead.

STL loaded, stones from the 3DM — automatically

If the STL arrived without stones (the usual case) but the design's Rhino or MatrixGold file exists, the studio reads the stone positions straight out of the 3DM — even one with no render meshes — and places a fitted gem at every one. The 3DM does not replace the model; it only adds the stones.

1. Load the STL first, as the model. When Auto Jewelry Setup finds no stones, a 'No stones found' prompt appears with an Upload .3dm button — click it and pick the 3DM. That is the whole job; skip to step 5.
2. If you dismissed the prompt, or the STL had some stones and you want the rest: open the Stones step, expand Add stones, and press Import from .3dm — it is the first button there. Pick the design's 3DM.
3. Or simply drag the .3dm file onto the loaded model. A 3DM dropped onto a model that is already loaded is read as 'place my stones', not 'replace the model'.
4. Wait for the toast: 'Placed N stones from <file>'. Every visible block instance in the 3DM becomes a stone, with its cut read from the block's name — Diamond_Round, Diamond_Pear, Emerald Square and so on.
5. Check the count against the design. If stones are missing, they are on a layer that is switched off in the 3DM — hidden layers are skipped on purpose, because jewellery files routinely park spare stones and second colourways on dead layers. If there are extra stones, something that is not a stone is a visible block: hide it in Rhino and import again.
6. Placed stones are real parts. Set their renderer, tune them, and they appear in every export exactly like stones the file brought itself.

STEP loaded — nothing needed, unless a name is wrong

A STEP keeps every body separate and carries its name, so the studio does the classification itself the moment the file opens: a part becomes a diamond if its name says so (stone, diamond, gem, brilliant, dia, cz, crystal, solitaire — or ruby, sapphire, emerald, amethyst for a coloured stone), or if it is tiny beside the largest part, or if it is a chunky, roughly equidimensional solid — the shape of a cut stone — rather than a thin band or a long prong. Everything else becomes the chosen gold. Usually that is the end of it.

It goes wrong in two ways, both from names. A stone called 'Body 14' with a big centre stone can still be caught by the shape test, but a small prong called 'Diamond_prong' becomes crystal; and a stone named after its colour — 'Emerald' — is read as a green stone even when it is a diamond in an emerald cut. Either way the fix is a selection and a click.

1. Load the STEP. Read the toast: 'N stones + M metal parts'. If the numbers match the design, you are done — go to the Stones step to choose the renderer, or straight to lighting.
2. If a diamond is showing as metal — usually because its body was named like a metal part, or not named at all: go back to the first step and select that diamond on the jewellery. Click it on the model, or click its row in the parts list (Shift-click to add more). The scope strip now says 'Applies to 1 selected part'.
3. With it selected, move to Metal & materials, open the Gemstones group and pick Diamond — or Ruby, Sapphire, Emerald, Amethyst. Only the selected part changes, and from then on it appears in the Stones section with every other stone, where its renderer and sparkle are tuned. The Stones section itself does not convert a part: it works on parts that are already stones.
4. If a prong or claw rendered as a stone: select it the same way and pick the gold it should be. It goes back to metal.
5. If a diamond came out green: it was named 'Emerald' for its cut. Select it and pick Diamond; the cut is geometry and is unaffected.
6. Clear the selection (the Clear link on the scope strip) before changing anything meant for the whole piece — a selection scopes every material and stone control to itself.
7. Next time, fix it upstream: name the stone bodies in the CAD program before export — Diamond_Round_1, Diamond_Pear_centre — and the classification never needs the guess.

Every file type, and what to do about the stones

The same three cases, for every extension the studio reads. The rule is simple: formats that keep separate bodies bring the stones as parts and the studio classifies them; formats that flatten to one mesh need the stones exported as untouching shells, or placed from the 3DM; and names only help where the format can carry them.

• .step / .stp — STEP: nothing to do. Every solid arrives as its own named part; stones are found by name, size and shape. If a diamond shows as metal, select it on the jewellery and pick Diamond in Metal & materials.
• .iges / .igs — IGES: bodies arrive separate but usually numbered, not named, so the stones are found by size and shape only. Check the count in the toast; fix any misses by selection, as for STEP.
• .brep — BREP: separate solids, no names or colours. Same as IGES: size and shape do the finding; select and pick Diamond for anything missed.
• .3dm — Rhino: the best case. Objects arrive as parts and the stone positions are read straight from the block instances, even when they were never meshed. Also the file to keep alongside any STL.
• .stl — STL: one mesh, no stones in most exports. Load it, then upload the design's .3dm from the Stones step's Add stones section (Import from .3dm) — or export the STL in parts with the stones as separate, untouching shells, and they are found by size and shape.
• .obj — OBJ: groups and objects arrive as parts, and names survive, so named stones are found. If the exporter dropped the stones, same remedy as STL: Import from .3dm or place by hand.
• .glb / .gltf — glTF: every mesh is a part, names survive, and a file that marks gems as gems is believed outright with no guessing. Use .glb so textures are packed.
• .fbx — FBX: each mesh a separate named part; stones found by name, size and shape. Fix misses by selection.
• .dae — Collada: scene tree as parts, names kept; as FBX.
• .ply — PLY: a scan or one mesh; parts only where shells do not touch; no names. Stones by size and shape, or from the 3DM.
• .3mf — 3MF: every object a separate named part with units — the print format that, unlike STL, keeps the stones if they were exported as objects.
• .amf — AMF: separate objects as parts, with units; as 3MF.
• .3ds — 3DS: objects as parts, but names are cut to 10 characters — 'Diamond_Ro' still says diamond; 'Brilliant_' does too. Check the count.
• .wrl / .vrml — VRML: scene structure as parts, names where written.
• .vtk — VTK: one surface, split where disconnected, no names. As PLY.
• .usdz / .usda — USD: meshes and hierarchy as parts, names kept; as glTF without the gem flag.
• .drc — Draco: one mesh, split where disconnected, no names. As STL — stones by shape, or from the 3DM.

Naming stones so they are always found

The name test runs before the size and shape tests and is the one you control. Rename the bodies in Rhino, MatrixGold, SolidWorks or Fusion before exporting and the studio reads the intent instead of guessing at it. Names survive STEP, 3DM and glTF; they do not survive STL, which has nowhere to put them.

• Say diamond outright: Diamond_Round, Diamond_Pear, Diamond_Emerald Square. A name that says diamond is a diamond whatever cut word follows.
• Coloured stones by their stone: Ruby_Oval, Sapphire_Cushion. 'Emerald' alone is read as the green stone.
• Do not put stone words in metal names: 'Diamond_prong' or 'Gem_seat' will be turned to crystal. Call them Prong_1, Head, Shank.
• Underscores and hyphens are fine; the studio splits them before matching.

The stones step is not always visible

The Stones step appears when the model is jewellery, or when at least one part carries a gemstone material. A STEP of a chair has no Stones step; a STEP of a ring whose category was guessed as 'product' shows one as soon as a part is made a diamond, or as soon as the category is corrected to a jewellery type at the top of the Model step — which also re-runs Auto Jewelry Setup. Everything here happens on your own machine: the file is converted and rendered in the browser through your GPU and is never uploaded, so an unreleased design stays unreleased.

Questions