Exporting an STL in parts

What 'in parts' means for an STL

The format cannot store parts, so the studio recovers them: on load it welds the mesh and then splits it wherever the triangles are disconnected. Every separate shell becomes a part. A stone sitting in its seat with a hair of clearance is its own shell, so it becomes its own part and is recognised as a stone; a stone that was Boolean-unioned with its prongs shares triangles with them, so it is one shell with the metal and cannot be separated afterwards. 'Export in parts' therefore means two things: export everything in one file, and make sure nothing that should be separate touches.

• One STL, all bodies selected — not one file per body; the studio loads one file
• Stones as separate objects, not unioned to the metal
• Names do not survive — the stones are recognised by size and shape, not by what you called them

Rhino

Rhino exports whatever is selected, at the mesh quality you choose in the dialog. Block instances — which is how most jewellery plugins store stones — are exported as their geometry, so they need no special handling.

1. Turn on every layer that holds metal or stones. Objects on hidden layers are not exported, and a hidden stone layer is the usual reason an STL arrives empty-seated.
2. Select the metal and the stones together — Ctrl+A if the file holds only this ring, otherwise window-select the piece.
3. Check nothing is unioned: click a stone; if the whole ring highlights, it has been joined. Undo the Boolean, or Explode and re-select.
4. File → Export Selected → STL. In the mesh dialog choose the detailed setting (or set Maximum edge length to about 0.1 mm for a ring). A coarse mesh shows facets on the shank that no material can hide.
5. Choose Binary. It is a fifth the size of ASCII and loads faster; nothing is lost.
6. Drop the file in the studio and read the Auto setup toast — the section below says what it should say.

MatrixGold

MatrixGold sits on Rhino, so the export is the same dialog with the same rules. The one thing to know is where the gems live: MatrixGold gems are blocks on their own layer, and the Gem layer is easy to leave switched off after a render pass.

1. In the layer panel, turn on the Gems layer along with the metal layers.
2. Select all the geometry of the piece, gems included.
3. File → Export Selected → STL, fine mesh setting, Binary.
4. Keep the .3dm. If the export goes wrong, the studio can place every stone directly from the 3DM in one click — which for a pavé piece is the faster route anyway.

SolidWorks

SolidWorks exports one STL per part file, or one for an assembly, and an assembly export has a setting that decides whether the parts stay separate.

1. Open the assembly (or the multi-body part) that holds metal and stones.
2. File → Save As → STL, then Options.
3. Set Resolution to Fine, or Custom with a small deviation. Set Unit to millimetres — an STL in inches arrives 25 times too small.
4. For an assembly, tick 'Save all components of an assembly in a single file'. For a multi-body part, ensure 'Do not translate STL output data to positive space' is ticked so the bodies keep their positions.
5. Save, and check the studio's toast for the part count.

Fusion 360

Fusion exports a mesh per body or per component, and the choice is in what you right-click.

1. Make sure stones and metal are separate bodies, not combined with a Join.
2. Right-click the top-level component in the browser → Save As Mesh (older versions: Save As STL).
3. Format STL (Binary), Refinement High, Unit millimetre.
4. Leave 'One file' selected so every body goes into the same STL.
5. Export and load it in the studio.

Reading the result

When the file opens, the Auto setup toast says how many stones and how many metal parts it found. For a solitaire the right answer is 1 stone + 1 metal part (or a few, if the head and shank are separate bodies). For a halo, the stone count should match the design. Two wrong answers, and what each means:

• 0 stones, 1 metal part, on a ring that has stones: everything welded into one shell. The stones were unioned to the metal — or the mesh was coarse enough that a stone's girdle touched its prongs. Re-export with stones separate, or place them from the 3DM.
• Far more parts than expected: the mesh has loose shells — split prongs, duplicate surfaces, a stray sprue. Usually harmless, but a claw that became its own tiny part may be taken for a stone; select it and give it the metal.
• Ring the wrong size: units. The STL was written in inches or centimetres. Re-export in millimetres.

When to skip all this

If you have the Rhino 3DM, you do not need the stones in the STL at all. Export the metal only, load it, and let the studio place every stone from the 3DM — exact positions, exact cuts, one click. The tutorial on STL, STEP and 3DM walks through it. 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