Files and geometry
STL
The oldest and most universal 3D print format. It stores a surface as a list of unconnected triangles and nothing else - no units, no colour, no material. Its silence about units is the single biggest source of scale errors in customer uploads. Compared in STL vs 3MF vs STEP vs OBJ.
3MF
The modern replacement for STL. A compressed, XML-based container that carries units, colour, multiple objects and slicer settings alongside the geometry - which is why a 3MF from Bambu Studio or PrusaSlicer can describe a whole multi-plate project rather than one lump of triangles.
STEP / STP
A precise CAD interchange format that describes true curved surfaces rather than triangles, so it has to be tessellated into a mesh before it can be sliced or priced. Small files, exact geometry, and the format an engineering customer will send you.
OBJ
A mesh format that can carry colour and texture through a companion material file, common in art, sculpting and 3D-scanning workflows. Geometrically it behaves much like STL.
Mesh
A surface built from flat polygons, almost always triangles. Everything a printer eventually prints is a mesh, even when the source was CAD - tessellation just happens earlier or later in the chain.
Manifold (watertight)
A mesh that encloses a solid volume with no holes, no duplicated faces and no self-intersections. Only a manifold mesh has an unambiguous volume, which is why non-manifold files break both slicers and automated quoting.
Bounding box
The smallest axis-aligned rectangular box that contains the model. It is what a maximum-part-size check tests, and the reason a part can fail in one orientation and fit in another - a proper fit check tries rotations rather than comparing raw dimensions.
Volume
The space enclosed by the mesh, in cubic millimetres or centimetres. Multiplied by material density it gives the mass of a fully solid part; multiplied by shell and infill assumptions it gives the mass you will actually print.
Surface area
The total area of the mesh's outer skin. It drives how much perimeter and how many shell passes a print needs, and it is a good proxy for finishing labour: two parts of equal volume can differ several-fold in sanding time.
Wall thickness (shell)
How thick the solid outer skin of a print is, usually expressed in millimetres or in perimeter count. Together with infill it decides how much of a part's volume is actually filled with material, and therefore what it weighs.
Complexity factor
A multiplier derived from the shape - typically the relationship between surface area and volume - used to reflect that intricate parts take longer per gram than blocky ones. It is how a geometry-based quote avoids underpricing lattices and overpricing cubes.
Printing and slicing
Slicer
The software that converts a mesh into printer instructions, deciding layers, perimeters, infill, supports and speeds, and producing the time and material estimates a quote can be built on. Bambu Studio, OrcaSlicer, PrusaSlicer and Cura are the common ones.
FDM
Fused deposition modelling: melting and extruding a filament along a path, layer by layer. The cheapest and most common process, and the one most service shops run.
MSLA (resin)
Masked stereolithography: curing a whole layer of liquid photopolymer at once with an LCD-masked UV light. Print time depends on the object's height rather than its volume, which changes the economics completely - see resin vs filament costs.
Infill
The internal lattice that fills the hollow space inside a print's shell, given as a percentage. Raising it costs material and time and buys strength; most functional parts live between 15% and 40%.
Layer height
How thick each printed layer is, typically 0.1 to 0.3 mm on FDM. Halving it roughly doubles print time and visibly improves surface finish, which is exactly what a precision tier sells.
Supports
Sacrificial structures printed under overhangs so they do not sag. They consume material that is thrown away and add manual removal time to every part, so a support-heavy model is more expensive twice over.
Brim and raft
Extra material printed around or beneath the first layer to improve adhesion. Both count towards the filament a job consumes even though neither is part of the finished object - a common omission when costing by hand.
Build plate
The printable surface, and by extension the batch of parts arranged on it. How full the plate is is one of the strongest levers on unit cost, dramatically so on resin.
Print time estimate
The slicer's prediction of how long a job will take. It is an estimate of one step, not of an order's lead time, which also includes queue, post-processing and packing.
Failure rate
The share of prints that do not complete usably. It is priced as a percentage buffer on cost rather than charged to individual customers - roughly 10% is a common starting assumption on a dialled-in FDM setup.
Post-processing
Everything done after the print finishes: support removal, sanding, gluing, assembly, and for resin a mandatory wash and cure. It is labour, so it belongs in the price explicitly rather than absorbed silently.
Costing and pricing
Cost per gram
Spool or bottle price divided by its weight, the unit that turns a model's mass into a material cost. A 25 dollar one-kilogram spool is 0.025 per gram. Engineering filaments can be several times that.
Hourly machine rate
One blended number per printing hour covering electricity, maintenance, consumables and depreciation, so those costs do not have to be itemised per job. Derived in how to calculate 3D printing cost.
Depreciation
Spreading a printer's purchase price across its useful life so every hour it runs carries a share of what it cost to buy. Ignoring it is why a shop can look profitable right up until it needs to replace a machine.
Markup vs margin
Markup is added to cost; margin is taken out of price. A 50 percent markup on 10 dollars of cost gives a 15 dollar price and a 33 percent margin - the two numbers are never equal, and quoting one while meaning the other is a recurring source of thin profit. Covered in 3D printing profit margin.
Minimum order value
A price floor applied after the formula, so a job too small to be worth handling is either raised to the floor or refused. It protects you from the fixed cost every order carries regardless of size.
Volume tier
A price break at a quantity or order-value threshold. It should discount the setup and handling cost that genuinely falls with quantity, not the material cost that does not - the arithmetic is in quoting B2B and bulk work.
Precision tier
A customer-facing quality option - draft, standard, fine - that maps to layer height and carries a price multiplier reflecting the extra machine time. It gives customers a cheaper option without you discounting.
Turnaround multiplier
The uplift charged for a faster promised delivery. What the customer buys is queue position, which is why it scales with the job rather than being a flat fee.
Cost-plus pricing
Deriving price by adding a markup to measured cost. It is the right starting point for custom work and the wrong stopping point, because it ignores what the market will pay - discussed in how much to charge for 3D printing.
Selling and operations
Draft order
A Shopify order built through the admin before payment, whose line items can carry a custom title and a custom price with no variant behind them. It is the mechanism that lets a quoted price become a real order - see custom order pricing on Shopify.
Line-item property
A text key and value attached to an order line, used to carry the model link, material, infill and derived weight. A property whose name starts with an underscore is hidden from the buyer at checkout but still visible in admin.
Lead time
The elapsed time from order to dispatch: queue, printing, post-processing, checks and packing. It is always longer than the slicer's print time, usually by more than people expect.
Quote expiry
A date after which a quoted price is no longer binding. It is the clause that protects you when material prices or your queue change, and it costs nothing to add.
Abandoned quote
A visitor who received a price and did not order. Recovering a share of them is usually cheaper than acquiring new traffic, which is why it is worth measuring separately from conversion rate.
Reverse charge
The common EU treatment for cross-border business-to-business supplies, where the seller invoices net and the buyer accounts for the VAT. It requires a validated VAT number recorded on the order, not in an email.
Made-to-order vs print-on-demand
Made-to-order means nothing is produced until it is sold, from your own catalogue. Print-on-demand in a printing context usually means producing from a file the customer supplies - which is the harder business, because the price is unknown until the file arrives.
Try the vocabulary on a real file
The free 3D printing cost calculator runs volume, weight, shell, infill and complexity on a model in your browser, so you can watch each of these terms move a number. Nothing is uploaded.
Open the calculator→FAQ
What is the difference between cost and price in 3D printing?
Cost is what the job consumes: material, machine hours, your labour and a share of the prints that fail. Price is what you charge, and it is a separate decision informed by markup, your minimum order value and what the market will bear. Confusing the two is the most common reason a busy print shop makes no money.
Why does infill affect the price of a print?
Because it changes how much material is actually inside the part and how far the nozzle has to travel to put it there. A part printed at 15 percent infill and the same part at 50 percent have the same outside dimensions but very different weights and print times, so any honest quote has to know which one the customer asked for.
What does non-manifold mean and why does it break a quote?
A non-manifold mesh has holes, duplicated faces or self-intersections, so it does not cleanly enclose a solid. Without an enclosed solid there is no unambiguous volume, and without a volume there is no weight and no defensible price. This is why an automated quoting tool has to detect and reject broken files rather than guess.