3D concrete printing guide
3D concrete printing makes it possible to produce free-form objects with a unique design without conventional formwork. The printer lays down the concrete mix layer by layer along a digitally prepared toolpath.
The technology is particularly well suited to producing curved, wavy, repetitive and parametric forms. However, the layered production method places some practical limitations on the object. The following recommendations will help you design a solution that can be printed, transported and installed reliably.
Our team checks every model before production and prepares the final toolpath on that basis.
Object dimensions
Print area
Our printer's work area is 7000 mm long and 3000 mm wide.
The maximum print height is not the same across the entire work area. The height limit varies along the length of the work area from approximately 300 millimetres to 1000 millimetres. The exact permitted height depends on the object's position in the printer's work area and is shown in the work area drawing.
A long object may therefore not fit within the maximum height limits along its entire length. The final placement is always checked against the work area drawing and the 3D model.
The object must fit entirely within the permitted working space. In addition to the object's dimensions, the clearance needed for the movement of the print head, nozzle and other machine parts must be taken into account.
Maximum printable object
The size of an object made in one piece is not determined by the printer's work area alone. The object's weight, centre of gravity, lifting, transport and installation site must also be taken into account.
A very long, tall or narrow object may be printable but difficult to move after setting. An object with a complex shape may need extra space for lifting slings, a forklift or other lifting equipment.
Larger objects can be produced as several separate elements. The parts are printed separately and joined after setting. Dividing into parts can also make sense for a smaller object if it simplifies transport, installation or the later replacement of individual components.
A good joint location is, where possible, visually concealed, does not weaken the object and allows the parts to be fitted together precisely.
Bead dimensions
The printer typically lays down the material as a bead 35–55 mm wide. The height of one layer is approximately 8–15 mm.
The exact dimensions are chosen according to the object's shape, size, material, printing speed and desired surface appearance. A lower layer reproduces the shape more accurately but increases the printing time. A wider bead produces a more solid wall but reduces the accuracy of small details.
The smallest practical wall thickness generally corresponds to at least the width of one bead. For a single-bead wall, allow for a thickness of approximately 35–55 mm. A thicker wall can be formed from several beads running side by side, an internal support structure or a cavity filled later.
Details smaller than the bead cannot be reproduced reliably. Very fine edges, narrow ribs, small recesses and thin peaks may disappear, deform or become rounded during printing.
The layers usually remain visible on a printed surface. This is the natural appearance of 3D-printed concrete, not a production defect.
Slopes and overhangs
An outward-sloping wall is created by offsetting each successive layer slightly from the previous one. The new layer must nevertheless be sufficiently supported by the layer below.
The permitted offset depends on the bead width, layer height, material, object height, printing speed and the time between layers. Slopes that are too steep may sag, twist or lose their shape during printing.
Inward-tapering forms are generally easier to print than forms that widen outwards quickly. For a bowl, vase or planter, it is worth designing the shape so that it widens gradually.
Large horizontal projections, shelves, roofs and bridges usually need additional support or a separately made component. It often makes sense to make the horizontal part from metal, timber, cast concrete or as a separately printed element.
For more complex overhangs, it may help to divide the object into parts, increase the wall thickness or make the shape less steep.
Toolpath
The outer shape of the 3D model is not yet the printer's path of movement. A toolpath is created from the model, which the printer follows in each layer.
The toolpath affects corners, joints, wall thickness, printing time and the object's stability. A smooth, continuous toolpath usually gives a more even result than a path with many interruptions and sharp changes of direction.
Closed toolpath
The most common and most reliable solution is a closed contour. The printer moves continuously around the object, and the start and end of the toolpath meet.
A closed toolpath is well suited, for example, to vases, planters, columns, lamp shells, bench supports and other hollow forms.
A closed shape reduces the number of times the material flow starts and stops, and helps keep the object stable.
Open toolpath
Walls with an open contour can also be printed. In this case, the printer moves in one direction in one layer and back in the next, or starts each layer anew.
At the ends of an open toolpath, the material flow must start and stop cleanly. As a result, the start and end points of the toolpath may differ slightly from the rest of the surface.
With open walls, very thin and tall free ends should be avoided. Where necessary, the ends can be thickened, rounded or tied into another wall, rib or intersecting element.
Long unsupported straight walls
A long straight wall may bend sideways or become wavy during printing, even if its thickness is otherwise sufficient. The risk increases as the wall gets taller, because the fresh material has not yet reached its final stiffness.
Very long straight sections are best avoided where possible. The wall can be stabilised with a slight curve, a wavy shape, an intersecting wall, an internal rib or local thickening. Sometimes it is enough to divide a long straight section into shorter segments at visually suitable points.
The exact maximum unsupported length cannot be determined from the drawing alone. It depends on the wall's height, thickness, material and printing speed, and is checked against the specific model.
Overlapping beads
Beads can be overlapped to connect walls, form intersecting parts or reinforce the structure.
This may be needed, for example, for partition walls, internal ribs, bench supports or multi-bead walls. The length of the overlap and the printing sequence are determined according to the model and the dimensions of the bead used.
An overlap that is too short can create a weak joint. An overlap that is too long can cause excess material to build up and visible thickening.
Object growing too fast in height
During printing, the lower layers must have enough time to stiffen before the weight of the following layers is added.
If the printer returns to the same area too quickly, the object grows in height faster than the fresh material can take the load. As a result, the wall may bulge, sag, lean or collapse.
This problem occurs more often with objects with a small circumference, because printing one layer takes little time. For a small vase or column, for example, the printer may return to the same spot with a new layer within a few seconds.
The rate of growth in height can be reduced by increasing the toolpath length of a single layer, printing several objects at once, adding a waiting time between layers or adjusting the material and printing speed. Sometimes it is useful to place several small products in the printer's work area and print them alternately.
The printability of an object is therefore not determined by its final shape alone. It also matters how fast the object grows in the Z direction, i.e. in height, during printing.
Corners and changes in shape
Sharp corners
A perfectly sharp corner cannot be formed with 3D concrete printing. The bead has a fixed width, so when the direction changes, the corner always remains slightly rounded.
Very sharp internal corners can cause material to build up. At sharp external corners, the bead may stretch or become uneven.
Rounded corners
Corners should, where possible, already be rounded in the model. A good starting point is a radius equal to at least half the bead width.
With Print Betoon's typical beads, this means a minimum radius of approximately 20–30 mm. A larger radius makes the printer's movement smoother and usually gives a cleaner result.
For decorative objects, a gentle transition, a wave or a chamfer can be used instead of a corner. Such solutions often suit the layered surface of 3D printing better than a classic sharp corner.
Rapid changes in shape
Very abrupt changes in width, wall thickness or direction should be avoided. If an object changes from very narrow to very wide within a few layers, the material may be distributed unevenly.
A smooth transition usually works better. Thickening or narrowing should take place over several layers rather than in one abrupt step.
Printing methods
Horizontal layering
Objects are generally printed in horizontal layers. This works well for forms with a flat base and walls that rise from the bottom up.
Horizontal layering is reliable and suitable for producing most products. With this method, a straight horizontal top edge usually comes out cleanest.
Stepped sloping surface
If the object's top edge is sloped, the horizontal layers make it stepped. The size of the steps depends on the layer height.
The lower the layer, the smaller and less noticeable the steps. With a slight slope, the edge may appear almost smooth. With a steeper slope, the layered geometry remains clearly visible and can be used as a deliberate design element.
If a perfectly straight sloping surface is required, it must be produced as a separate component or treated after printing.
Internal wall structure
An object does not have to be completely solid. The wall may contain an empty cavity, a wavy infill, internal ribs or a core filled later.
A hollow solution reduces weight and material consumption. Internal ribs can increase stiffness and help maintain the shape during printing.
For planters, benches and other larger products, space can be left inside for reinforcement, fixings, infill concrete or technical components.
The internal geometry must be open enough for the printer to complete all toolpaths without the nozzle or machine parts colliding.
Openings and fixings
Openings, penetrations and fixing points should, where possible, be planned before printing.
Vertical openings and cavities are usually easy to produce. Openings with a horizontal top edge may need an arched shape, temporary support or a separate lintel.
Smaller openings can be drilled after the concrete has set. For very precise bolt holes or fixing surfaces, it often makes sense to drill them afterwards or use a separately installed metal part.
Threaded rods, anchors, lifting inserts or other components can be embedded in the object during printing. Their position, size and installation sequence must be agreed in advance.
Base and top
The printer is best suited to producing walls and upright forms. A fully closed base or a large horizontal top surface is usually not printed directly.
The base can be made separately, cast later or added from another material. For a smaller object, the base can sometimes be formed with layers gradually moving inwards, but this depends on the shape and the stability of the material.
The top can be made as a separate slab, lid, seat or other component. For example, the printed legs of a bench can be combined with a seat made of timber, metal or cast concrete.
Accuracy and surface quality
3D concrete printing is not as precise as metalworking or printing small plastic parts. The fresh mix may deform slightly under its own weight, and the edges naturally remain rounded.
Dimensions are affected by the consistency of the material, the weather, drying and setting. With a tall or thin object, small deviations may accumulate layer by layer.
The printed surface may remain naturally layered. Where needed, it can be partly smoothed, sanded, painted or treated with a protective product.
Achieving a very smooth surface requires additional manual work and may make the natural appearance of 3D printing less visible. It often makes sense to use the layered surface as a deliberate design element.
Dividing the object into parts
Objects that are larger or more complex than the printer's work area allows can be produced as several separate elements.
Joint locations are planned so that they are easy to connect and do not spoil the object's appearance. The joint can be straight, stepped, tongue-and-groove or shaped to follow the object's form.
Dividing into parts can simplify lifting, transport, surface treatment and installation. It can also make it possible to replace a damaged component separately later on.
Depending on the product, the finished elements are joined mechanically or by bonding, grouting, bolting, internal infill or another suitable solution.
Technical data
| Parameter | Print Betoon |
|---|---|
| Printer work area | 7000 × 3000 mm |
| Maximum print height | Approximately 300–1000 mm, depending on the object's position in the work area |
| Bead width | 35–55 mm |
| Layer height | 8–15 mm |
| Smallest practical wall thickness | Generally at least the width of one bead |
| Recommended minimum corner radius | Approximately 20–30 mm |
| Long straight walls | Depending on height and thickness, require curves, ribs, intersecting walls or other stiffening elements |
| Rate of height growth | The lower layers must have time to stiffen sufficiently before the following layers are added |
| Overhanging surfaces | Assessed according to the model, material and chosen printing parameters |
| Standard printing method | Horizontal layers |
| Surface texture | With naturally visible print layers |
| Preferred 3D files | 3DM and STEP/STP |
| Other usable 3D files | STL, OBJ and SKP |
| Drawings | DWG, DXF and PDF |
| If there is no model | Dimensioned sketch, drawing or photo |
Which files to send?
The best starting point is a 3DM or STEP file at the correct scale containing the final geometry.
| File format | Suitable for | Key requirements |
|---|---|---|
| 3DM | Rhino and Grasshopper models | The final geometry must be clearly separated from construction geometry. Parts and layers should be named. |
| STEP / STP | SolidWorks, Solid Edge, Inventor, Fusion 360 and other CAD | Preferably closed solids. Unnecessary details smaller than the print resolution can be removed. |
| STL | Finished mesh model | The model must be closed, at the correct scale and free of holes, overlapping faces and self-intersections. |
| OBJ | Free-form mesh models | The same geometric requirements as for STL. Textures are not usually needed for production. |
| SKP | Simpler SketchUp models and initial assessment | The geometry must form closed volumes. Parts should be in separate groups or components. |
| DWG / DXF | Plans, sections and contours | Lines must be at the correct scale. Closed contours should be genuinely closed polylines. |
| Drawings and explanatory project material | Include the unit of measurement, main dimensions, views, a section and a note of the current version. A PDF does not replace the 3D model needed for production. |
The file should contain only current or clearly labelled geometry. It is worth removing old versions, unnecessary copies, hidden objects and small details that are not needed for production.
The model's unit of measurement should be millimetres. The object's bottom surface and intended print orientation must be clearly identifiable. If the object consists of several elements, these should be separate solids, groups or layers and logically named.
Openings, joints, fixings and any required precise surfaces must be shown in the model or an accompanying drawing. If not all information can be included in the 3D model, a dimensioned PDF drawing can be added.
When sending a Grasshopper definition, include the 3DM files, data files and other external content used. Also state the names and versions of the plugins used.
The file name should include the object's name, version and date, for example:
planter_V03_2026-07-28.step
What to include in a quote request?
The most important things in a quote request are a drawing or model of the object, approximate dimensions, the desired quantity and the place of use.
It is also worth including the desired colour and surface finish, whether the object will be used indoors or outdoors, the need for fixings, the transport and installation site and the desired completion date. Please also state if the object must carry people, soil, water or any other significant load.
Not every detail has to be finalised before you get in touch. An initial idea is often enough, as a small change in shape can make the product easier to print, stronger, lighter or more affordable.
Is your idea suitable for 3D concrete printing?
Send Print Betoon a 3D model, drawing, photo or dimensioned sketch.
We check the object's printability, assess whether it fits the printer's work area, suggest changes where needed and prepare a production-ready model and toolpath.