Reconstructing Medieval German Towns with 3D Printing

Posted by FIT THAI on July 16, 2026

3D reconstructions based on ancient cities are of great importance for archaeologists, (art) historians, and architects. They are used not only to illustrate cities but also to better understand historical events and to provide a virtual representation of the past.

The three cities of Worms, Speyer, and Mainz, known as the SchUM cities, are of historical value, and their development is of particular significance. As some of the most influential communities of the Holy Roman Empire in the Middle Ages, these cities developed into pillars of imperial power and socio-cultural centers. To gain a deeper understanding of the medieval world, the Rhineland-Palatinate State Cultural Heritage Office, under the direction of former director Metz, and in cooperation with the Faculty of Architecture at Mainz University of Applied Sciences, decided to reconstruct all three cities in 3D. The result is a special exhibition featuring six large-scale models, which recreate the cities in 800 AD and 1250 AD. These models consist of more than 650 individual parts and were all created using stereolithography (SLA) 3D printing technology.

The reconstruction of the three cities at two different points in time consists of over 650 segments, each measuring 12x12 cm, and was printed using Formlabs White Resin.

Development of imperial cities along the Rhine River
The Mainz Institute for Architectural Research (AI MAINZ) is an applied research institute at Hochschule Mainz University of Applied Sciences. As an interdisciplinary institute, AI MAINZ combines architecture, (art) history, and applied computer science.

This interdisciplinary fusion is also evident in their latest project, which involved over 50 participants from different departments. The project began in September 2018 with the goal of visualizing the development of the three cities of Worms, Speyer, and Mainz around the year 800, when the decline of the Roman Empire began, and their subsequent development up to 1250.

In cooperation with archaeologists and (art) historians from the Rhineland-Palatinate State Cultural Heritage Office, as well as archaeological excavations and existing structures, the cities were meticulously digitally reconstructed in every detail. "We wanted to show the development of all religions in the cities. In every city, there were Jewish quarters, and by 1250, there were Romanesque cathedrals of immense importance, which were connected to the emperors and the structure of the cities," says Igor Bajena, one of the team members responsible for digital and physical visualization and project implementation.

The three cities were divided into segments on a grid, resulting in more than 650 individual segments representing two different periods.

Attention to detail, essential for SLA
Due to the required detail and accuracy of each segment, SLA 3D printing was the ideal choice. "The details are much more visible, and the aesthetics meet our requirements," says Aliya Mahmood, who co-led the project with Mr. Bajena from start to finish. AI MAINZ currently has four Form 2 machines and three Form 3 machines in operation, which contributed to the success of this project.

AI MAINZ used four Form 2 and three Form 3 SLA 3D printers to complete this project.

With the reliability of the Form 2 and Form 3, Ms. Mahmood and Mr. Bajena were able to print over 650 segments with 3D printers over the course of the project, and the SLA 3D printers were able to run continuously during this time. The printers were only paused for cleaning and resin tank changes, allowing them to continue operating at maximum resolution and consistent accuracy. During this time, the Formlabs support team provided assistance. Aliya Mahmood, who is responsible for the maintenance and operation of all seven SLA printers, stated, "Formlabs helped us tremendously throughout this entire process."

When the models of the three cities are assembled at a scale of 1:1000, they have the following dimensions:

Reconstruction of Worms in 800: 116.7 cm x 108 cm, height from 0.9 cm to 4.0 cm.
Reconstruction of Worms in 1250: 116.7 cm x 108 cm, height from 0.9 cm to 7.9 cm.
Reconstruction of Speyer in 800: 252 cm x 159.8 cm, height from 0.8 cm to 3.3 cm.
Reconstruction of Speyer in 1250: 252 cm x 159.8 cm, height from 0.8 cm to 8.8 cm.
Reconstruction of Mainz in 800: 168 cm x 204 cm, height from 0.8 cm to 6.6 cm.
Reconstruction of Mainz in 1250: 168 cm x 204 cm, height from 0.8 cm to 7.5 cm.

The dimensions and segmentation were based on the build volume of the Form 2 and Form 3.

One of the project's objectives was to make visible how the Romanesque cathedrals around 1250 were connected to the respective emperors and the structure of the city.

Given the architectural standards and the required level of detail, Mahmood and Bajena used Formlabs White Resin. Its neutral tone, detail precision, and matte finish allowed for optimal conditions without complex post-processing. "The White Resin shows details very well, and the segments are much smoother. From the moment it comes out of the printer, a good-looking, finished model is already there," Mahmood said.

By using Formlabs White Resin, Mahmood was able to create beautiful models right out of the printer and maintain the high level of detail required for the project. These details are particularly visible in the Romanesque Cathedral in Speyer around 1250.

Workflow for producing scale models

After the 3D printed parts are removed from the printer, each segment undergoes a regularly defined workflow that requires extreme delicacy.

Washing
To remove excess resin and prepare for the next step, each segment is first washed with isopropyl alcohol (IPA) in a Formlabs Form Wash.
Support Removal
After removing the segments from the build platform, the support material is removed in two steps. First, flush cutters and tweezers from the finishing kit are used to carefully remove small structures on and within the buildings. During this step, extreme care must be taken with segments that have small details and openings, such as cathedrals, to prevent any parts from breaking. In the second step, the larger support material at the bottom of the segments is removed and smoothed.
Sanding
To remove traces of support material and make details more visible, each part is sanded and shaped by hand. During this step, care must be taken not to sand too much, so that each part connects and transitions smoothly.
Painting
In the final finishing step, each part is spray-painted white with a spray gun in two coats. This improves the surface finish of the segments and highlights fine details particularly well.

Due to the delicate structure and details of each part, the post-processing is extremely time-consuming. If a building breaks, gets damaged, or is sanded too much, the part must be reprinted, which leads to a loss of valuable time.

From 3D Printer to the Mainz State Museum

After two years, 650 segments, and over 22,000 hours of work, the cities of Worms, Speyer, and Mainz were assembled into final models of each city at two different time periods.

Visitors can view and compare the historical development of the medieval cities, physical reconstructions, and various models in the newly opened Digital Urban History Laboratory. This hybrid laboratory is a collaboration between the Time-Based Media program of the Faculty of Design at Mainz University of Applied Sciences, the Institute for Architectural Research, and the Rhineland-Palatinate State Cultural Heritage Office, and has become an indispensable part of the state exhibition on the theme "Emperors and Their Pillars of Power: From Charlemagne to Frederick Barbarossa."