6 min read
Rendering models vs printable models
A model that looks perfect in a render can fail to print. Rendering software only needs visible surfaces; a 3D printer needs closed, solid volumes with real thickness. Walls modeled as single faces, overlapping objects and tiny details below printable size are the most common problems.
General rules for any software
- Make every object a closed (watertight) solid with no holes or open edges.
- Remove what you will not print: furniture, people, trees, interior details at small scales.
- Set the scale before exporting and check the export units are millimeters.
- Thicken elements that fall below about 1 mm at the model scale.
- Merge touching objects, or make sure they overlap slightly so the slicer treats them as one part.
SketchUp
SketchUp models are often built from single faces, so check that each object is a solid group or component; the Entity Info panel shows when an object is a solid. Fix reversed faces, delete stray edges and use extensions such as Solid Inspector to find problems. Export as STL, choosing millimeters as the unit.
Revit
Create a dedicated 3D view for printing and hide categories you do not need, such as furniture, annotation and MEP systems. Use a section box to isolate the part of the building to print. Export through an STL exporter add-in or via FBX/OBJ into a mesh tool, then repair the mesh before slicing. At small scales, simplify window mullions and railings, which become too thin to print.
Rhino and ArchiCAD
In Rhino, use the ShowEdges and Check commands to find naked edges, and join surfaces into closed polysurfaces before meshing. In ArchiCAD, export a 3D view to a mesh format and repair it in a mesh tool if needed. The same principles apply: closed solids, correct scale and enough thickness.
Repair and slice
Open the exported file in your slicer. Most modern slicers can repair small mesh errors automatically and show thin walls that will not print. Split large models into floors or blocks, add alignment pins if needed, and preview the layers before printing to catch missing details.
Need a printer that handles big models?
Jordan Automation supplies FDM printers, filament and spare parts in Amman for architecture offices and students. Send us your typical model size and we will recommend a suitable printer.
Frequently asked questions
Which file format should I export for 3D printing?
STL is the universal choice. 3MF is increasingly supported and can keep colors and units, which is useful for multi-color prints.
Why are some walls missing in the sliced preview?
The walls are probably thinner than the nozzle width at your model scale, or they are single faces without thickness. Thicken them in the design model.
Do I need to model the building differently for printing?
Usually you work from the same model but create a simplified print version: solid volumes, no interior clutter and elements thickened for the scale.