To 3D print jewellery from a Rhino file, export your design as a closed, watertight mesh (STL or OBJ) with a fine enough tolerance to hold the detail, check the wall thickness survives the print and cast process, then send it either to your own resin printer or to a casting bureau, depending on volume, turnaround, and how tight your tolerances need to be. That’s the short version. Here’s what each step actually involves, from the chair I teach it from as a Rhino trainer at an Official Rhino Training Centre in Birmingham’s Jewellery Quarter.
Exporting a clean mesh
Rhino works in NURBS, exact mathematical surfaces. A 3D printer, and the casting house behind it, works in a mesh: thousands of small flat triangles approximating those surfaces. The export step is where one becomes the other, and it’s where most avoidable problems get baked in.
Before you export, check the model is a single closed polysurface, no gaps, no naked edges, no overlapping shells. Rhino’s SelBadObjects and ShowEdges (set to naked edges) will find most of what’s wrong before you waste a print on it.
When you export to STL, the tolerance setting controls how closely the mesh triangles hug the true curve. Too coarse, and smooth bezel walls and pave seats come out faceted, visible to the eye and painful to a stone setter. Too fine, and the file balloons in size for no benefit the printer can actually resolve. For jewellery-scale work, a tighter tolerance than Rhino’s default is almost always worth setting deliberately, and matching it to your printer’s own resolution rather than guessing is the right habit.
Wall thickness, before you print, not after
This is the check that saves the most heartache, and it’s the one most new CAD students skip because the screen shows a perfectly solid-looking piece.
As a rough guide for cast wax or resin printing, walls thinner than around 0.3 to 0.4 mm are where trouble starts: the print itself may hold, but it becomes fragile to handle, and it can fail during the burnout stage of casting, when the pattern is heated inside investment plaster before molten metal replaces it. Walls in the 0.6 to 0.8 mm range and up are comfortably survivable for most non-structural elements. Anything load-bearing, a shank, a claw, a hinge, wants to sit at the thicker end of that range or beyond, because the finished cast piece has to survive daily wear, not just the printing and casting process.
Check this in Rhino before you export, not after the print comes back broken. A quick section cut through the thinnest-looking areas of your model, measured directly, tells you more than eyeballing the render ever will.
In-house printer or casting bureau
The decision here usually comes down to three things: volume, turnaround, and how tight the tolerance needs to be.
A single prototype or a one-off bespoke commission, where you want to hold the physical model in your hand within a day and iterate on fit before committing to metal, suits an in-house resin printer well. You control the schedule entirely, and the feedback loop between “adjust the file” and “hold the new version” is as short as it can be.
Higher volume, or tolerances tighter than a desktop resin printer reliably holds, is where a casting bureau earns its place. Bureaus run industrial-grade printers calibrated for jewellery-scale detail, and most also handle the casting itself, so you’re sending a file and receiving a cast piece rather than a wax pattern you still need to get cast elsewhere. The trade-off is turnaround: you’re working to their schedule, not yours, and lead times need to be planned into a commission timeline rather than assumed away.
Casting pattern versus wearable print
There’s a real difference between printing a wax or resin pattern destined for the casting process, and printing a piece in a printable metal to be worn as-is.
A cast wax or resin pattern only has to survive long enough to be invested in plaster and burned out. It never touches a finger. That means the printer’s job is purely about capturing geometry accurately: the metal that replaces it in casting is what actually has to survive wear, and traditional casting alloys behave in ways jewellers have understood for a very long time.
Printing directly in a metal, generally by a specialist bureau using metal powder-bed printing rather than a desktop machine, skips casting altogether: the printed piece is the finished piece. That route changes the design brief. Wall thickness minimums usually shift, support structures need designing into the file rather than added afterwards, and the surface finish out of the printer is rougher than a cast-and-polished piece, so more finishing work happens after the print rather than before it. It’s a genuinely different production route, not just a faster version of the same one, and which one suits a given piece is a design decision worth making before you model it, not after.
If you want to do this one-to-one, at the studio in Birmingham’s Jewellery Quarter or online, start with a free 30-minute call: Jewellery CAD, taught one-to-one.