3D Model Making Materials Explained: Resin, Finishes & Bases
When architects commission a physical model, the choice of material rarely gets the attention it deserves β yet it's the single biggest factor in how a model looks, feels, and holds up under studio lights or a jury's scrutiny. Understanding what goes into a professional 3D printed architectural model β from the resin itself through to the finishing and the base it sits on β helps architects brief projects more effectively and set realistic expectations for cost and turnaround. It also helps to understand how 3D model makers actually work with these materials day to day.
The Core Material: SLA Resin
Fixie 3D builds its architectural models using Stereolithography (SLA), a process where a UV laser selectively cures liquid photopolymer resin, layer by layer, into a solid form. Unlike filament-based (FDM) printing, which leaves visible layer lines and often needs extensive finishing work to look presentation-ready, SLA produces a smooth, high-resolution surface straight off the printer β making it the standard choice for 3D model makers working on architectural projects where crisp edges, thin walls, and fine detail matter.
This resolution advantage is what allows Fixie 3D's large-format printers, with a build volume of 750 x 750 x 550mm, to capture intricate massing, façade detailing, and site context in a single piece, or across a multi-piece model when a project's scale demands it.
From Print to Presentation: The Finishing Process
A model straight off an SLA printer isn't the finished product β it's the starting point. After printing, parts go through several stages of hand finishing carried out by experienced 3D model makers:
Support removal and clean-up β uncured resin is washed away and supports are carefully detached
Sanding β progressive sanding smooths any residual seams or surface imperfections
Priming β a high-build primer evens out the surface before paint is applied
Spray finishing β Fixie 3D's in-house spray finishing team applies matte, satin, or gloss coatings to represent different materials β concrete, glass, metal, and more β giving a single-material print the visual variation of a real building
Masking and detailing β selective masking is used for glazing lines, material breaks, or landscape bands, which helps a model read clearly even at small scale
This is where the craftsmanship side of model making comes in. Skilled 3D model makers use traditional tools β scalpels, rulers, airbrushes β to bring a bespoke, hand-finished quality that printing alone can't replicate. The result is a model that combines the geometric precision of digital fabrication with the tactile realism of traditional model-making techniques.
Bases and Assembly: Bringing It All Together
For larger or more complex projects, a model is rarely printed as a single object. Fixie 3D uses a site plug system, where each building or phase of a masterplan is produced as a separate, swappable component. This means a design can evolve β new options reprinted and slotted in β without remaking the entire model from scratch. It's a particularly useful approach for projects still in active design development, or for competition models where multiple massing options need to be presented side by side.
Once the individual pieces are finished, they're assembled by hand using alignment pins, adhesives, and internal stiffeners to ensure the model is robust enough to transport safely β whether that's across London or on a flight to a competition jury. Multi-piece models are then typically mounted onto CNC-cut bases, produced in-house, which give the finished piece a clean, professional presentation edge and make it easier to display, carry, or ship.
Why Material Choices Matter for Architects
Every stage β resin, finish, base β has a direct impact on cost, turnaround, and how well a model communicates a design. A simple, single-piece SLA print with minimal finishing can be turned around in as little as 2β3 days. A large, multi-piece model requiring full spray finishing, masking, and a mounted base is a more involved build, typically taking 10β14 days depending on complexity, since it demands closer attention from the 3D model makers handling assembly and detail work.
Knowing this in advance helps when briefing a model: if you need something for an internal design review, an unpainted or lightly finished print might suffice. If it's heading to a client presentation or competition panel, factoring in time for full spray finishing and a properly mounted base is essential.
Working With the Right Files
None of this is possible without a clean starting file. Fixie 3D accepts models exported from Revit, AutoCAD, Rhino, and SketchUp in STL, OBJ, or FBX format, using Materialise Magics to prepare and repair files before printing begins. Getting geometry watertight and correctly scaled at the file stage avoids delays further down the line β something the team of 3D model makers, with over 15 years of experience working across the AJ Top 100 and beyond, has refined into a reliable, repeatable process.
The Takeaway
A 3D printed architectural model is never just "a print." It's a combination of resin technology, hand finishing, and considered base design β each element chosen by skilled 3D model makers to make sure the final model does justice to the design it represents. Understanding these material choices upfront helps architects brief projects with confidence, and get a model back that's ready for whatever room it needs to stand up in.
At Fixie 3D, our team of experienced 3D model makers combines precision SLA resin printing with in-house spray finishing and CNC-cut bases to deliver presentation-ready models for architects across London and the UK. From file preparation through to final assembly, every stage is handled under one roof β no juggling multiple suppliers, no compromise on quality.
