prof. Dr. Henri Hubertus Achten

prof. Dr. Henri Hubertus Achten, Ing. arch. Vasilisa Supranovich

15116 Ústav modelového projektování

Virtual reality is an important tool for architects, allowing them to present the future object to the client from the early stages of design. A scene in virtual reality can be presented in two ways: by a VR headset connected to a computer or in standalone mode. With high-quality optimization, standalone VR systems can demonstrate graphics that are not inferior to VR devices connected to a computer, while remaining mobile, allowing the architect to flexibly organize meetings with the client. An effective scene optimization system is also necessary for stable and high FPS, which directly affects the comfort of the user experience and immersion in VR. Since models for architectural visualization are often not intended for use in VR, optimization of their geometry is necessary. Using manual optimization gives more control over preserving the visual quality of a 3D object and does not violate the UV-map structure, unlike the automatic optimization method. Creating retopology and using normal maps allows to preserve the level of detail of objects without increasing the number of polygons and thus reducing the load on the graphics card. The experimental part of this work examines in detail the effect of scene optimization on its performance. As part of the study, 2 scenes were created: the first included 3D models of interior elements downloaded from archviz sites, and the second - their optimized versions created as part of this work. In the next step, the performance of both scenes is analyzed and the impact of 3D object optimization on the overall efficiency of the scene is assessed. The ability to work with optimization allows the architect-visualizer to create high-quality realistic projects that enable the future structure to be presented favorably and increases efficiency in working with the customer.

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prof. Dr. Henri Hubertus Achten

Since its first massive media breakthrough after 2007, the concrete 3D printing technology has been hailed by many as a game-changer that would change the future face of construction manufacturing and the face of buildings in general. A great deal of effort and resources have been invested in the development of this robotic technology on the global scale over the past decade, yet even after all these years, we have not witnessed its massive deployment on the construction site. This thesis seeks to describe the specifics of the concrete 3D printing technology from both technology and material perspective and to answer the question of what are the key areas regarding applicability of the 3D printing by extruding one component mixtures in the production of concrete components with high quality requirements. The work is supported by the author's more than six years of experience with the topic of the thesis and the practical skills required to master it, i.e. designing and building printers, manufacturing extrusion nozzles and print heads, preparing and testing printing materials and programming the controlling scripts. In the introduction of the thesis, the author summarizes the current state of knowledge in the field of 3D printing by mortar extrusion. In the hypothesis, he names critical areas, the mastery of which will be crucial for the practical application of the technology. In the following sections, methods for achieving the objectives of the thesis are proposed. The process of designing printing materials and possible ways of designing the controlling scripts are described and the applicability of selected test methods for verifying print material parameters is discussed. Then, using specific case studies, the practical part demonstrates the pitfalls accompanying the printing process due to the specifics of the machinery, variations in the quality of input raw materials and the influence of the surrounding environment on the 3D printing process and the quality of the final print. The results obtained by the author are further analysed in order to assess individual aspects of the material preparation process and the printing process itself. In the conclusions, the author summarizes the findings and suggests the conditions for the applicability of the 3D printing technology in practice.

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prof. Dr. Henri Hubertus Achten

15116 Ústav modelového projektování

Digital twin technology is often overlooked in early architectural design stages, with most studies focusing on final applications and performance evaluation. Our research bridges this gap by exploring hybrid prototypes, combining digital and physical models enriched with sensors by a "foetal" digital twin during conceptual design, representing the eventual "adult" version. Physical twins collect data, while digital twins simulate and optimize within these prototypes. We utilize a foetal physical twin collecting and transmitting data for a more sustainable architectural design process.

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prof. Dr. Henri Hubertus Achten, Ing. arch. Jiří Vele, Ph.D.

15116 Ústav modelového projektování

This paper explores improvements in 3D Concrete Printing (3DCP) buildability using non-planar layering. Our proof-of-concept experiment validates the assumption that non-planar layering enhances the buildability of overhangs and vaults. To test this, we designed an object comprising two columns with a Gothic arch and overhangs on the upper part, resulting in a continuous wall at the top. The object measures approximately 1.5 meters in length, 400 mm in width, and 700 mm in height. The design was executed to maintain the centre of mass in the centres of the columns across all print layers, mitigating unwanted deformation. The overhang angle ranged continuously from 0 to 70 degrees. The object was modelled in Rhinoceros software, and G-code for both planar and non-planar printing was generated in Grasshopper. Both samples were designed to use the same amount of material, print length, and print time. We printed these using a cementitious mixture with plastic fibres and an additional accelerant mixed in the nozzle on a gantry printer. Throughout the printing process, we conducted careful observation and monitoring to detect any instances of buckling or collapse. Post-print measurements were carried out to evaluate the deformation of the printed objects, revealing a reduction in deformation with non-planar printing. This paper discusses the analysis of results and proposes a workflow for future data preparation for non-planar slicing.

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prof. Dr. Henri Hubertus Achten, doc. Ing. arch. Kateřina Sýsová, Ph.D., Ing. arch. Lukáš Kurilla, Ph.D., Ing. arch. Šimon Prokop, Ing. arch. Jiří Vele, Ph.D.

15116 Ústav modelového projektování

The contemporary landscape of construction 3D printing of materials like clay or concrete mainly relies on planar slicing, which, regrettably, impose constraints on the realization of overhangs and cantilevered structures, thereby limiting architectural design flexibility and posing issues in fabricating intricate structures. In response to this challenge, we investigate the integration of non-planar slicing in the construction printing of structures featuring substantial overhangs. We present a novel approach to crafting print paths strategically, fragmenting the global overhang into discrete local segments. Additionally, we introduce self-balancing control to help the buildability within segments of the print path, elevating the stability of the freshly deposited concrete during the printing process. Our methodology redistributes a portion of the bending forces into tension forces oriented along the print path, thereby augmenting the structural integrity and buildability of intricate structures with overhangs and vaults. The efficacy of our method is demonstrated through a computational parametric model and a physical prototype. A comprehensive comparative analysis is conducted against conventional planar printing methods, encompassing metrics such as geometric accuracy, buildability, material efficiency, and print time.

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prof. Dr. Henri Hubertus Achten, Ing. arch. Jiří Vele, Ph.D.

15116 Ústav modelového projektování

While the CAD model is being prepared for 3D printing, it is sliced into layers. Contrary to planar slicing, where an object is cut by horizontal planes and then a curve for the toolpath is generated from these intersections, non-planar slicing uses twisted planes for object cutting. It brings freedom to toolpath creation and each object can be printed in adjusted layers that reflect its geometry. Benefits of such printing are being explored in plastics and involve enhanced surface finish, cracking reduction and ability to print cantilevers. This paper examines printability of overhangs using clay non-planar printing. Basic potter's clay, from an art supplies shop was mixed with additional water and let in room temperature for one day. Desktop FDM delta printer was retrofitted with a clay printhead, its extruder motor was geared into a 19:1 ratio and connected to the ram. This ram pushes clay from a tank and nylon tube through a 4mm thick nozzle. Set of vase-like objects was designed, each with a different overhang. Starting at 10 degrees and ending at 70 degrees, in increments of 5 degrees. Objects were modelled in Rhinoceros software and G-code for both planar and non-planar print was generated in Grasshopper. Each of those objects were printed twice, once planarly and once non-planarly. During the printing buckling and collapsing of printed objects was monitored. Non-planar printing improves buildability and reduces deformation of overhangs. Right after the print and after they got dry, objects were measured for their deformation. Shrinkage during the drying was measured to be 12,5%. Ideal toolpath for non-planar printing seems to be the one having layers perpendicular to the overhang. Model evaluation and non-planar printing data preparation is being discussed in the paper. If used on a large scale, non-planar printing may allow printing walls with holes for plumbing, or even printing vaults or bridges.

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prof. Dr. Henri Hubertus Achten

15116 Ústav modelového projektování

The digital twin concept is defined as a trio of physical counterparts, vir- tual counterparts, and their connections. A digital twin, which is used in many industries, can be a simultaneous reflection of a building and its design scenarios, digital versus physical or physical versus digital, in the architectural design realm. Specifically, our focus is on the built envi- ronment, where hybrid prototypes can use several sensors, actuators, and processors to simultaneously collect and react to data by applying digi- tal twin technology while still in the design process. Hybrid prototypes extend physical models as we know them today with digital models sup- ported by digital twin technology. The foetal digital twin is at the start of the concept design and can be in the form mainly of simulations or a physical scale model combined with some sensors. The child digital twin can be a door or window model, facade prototype, shading system mock-up, or wall prefabrication fitted with sensor technology. Here, we hypothesise that foetal and child digital twins may be appropriate stand- ins for adult digital twins through the design process. Therefore, we try to determine how we can have better foetal, child, and adult physical and digital twins. To accomplish this, we provide an architectural design cat- alogue that includes sensors during prototyping to guide designers. Sen- sor network establishment is one of the first tasks that can be performed for a digital twin. The sensed data from the physical prototype will be used in a digital twin to actuate and monitor the status, and the digi- tal prototype will be used for the simulation, optimization, and predic- tion of future status. Eventually, data combination will be achieved with the help of Building Information Modelling and the Internet of Things. To guide the design process efficiently, it is important to decide where the sensors will be because, after the final design and operation, things will be handed over to a facility manager.

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prof. Dr. Henri Hubertus Achten, Ing. arch. Lukáš Kurilla, Ph.D., Ing. arch. Jiří Vele, Ph.D.

15116 Ústav modelového projektování

The traditional method of data preparation for 3D printing, known as planar slicing, involves slicing the 3D model into horizontal layers and printing them gradually. This is the simplest option with the main parameter being layer height. However, this method has several limitations, including poor surface finish with stair-stepping contours of layers at steep angles and a necessity to print additional support structure for overhangs. Nonplanar slicing is a newer method that involves slicing the 3D model into non-horizontal layers with varying layer heights. This technique is mostly explored in plastics, with observed improvements in buildability, surface finish and reduction of cracking alongside the layers. In construction scale, non-planar printing is used primarily for achieving unique surface finish, or for printing on an uneven base. Its potential for improving buildability is still yet to be properly tested. This paper examines how non-planar layers can be derived with a help of force flow lines and how it affects the buildability. While printing overhangs, shear force can ultimately break the interlayer bond and layers can start deforming and sliding on top of each other, resulting in buckling, or even collapse. By guiding these forces into the bulk of layers instead of interlayer bonds, printing capabilities can be improved. Goal of this paper is to present how buildability of overhangs can be improved using non-planar slicing. Non-planar layers are derived from force flow line simulations done in Karamba3D. For printing we use clay, as a fast and simple prototyping method with the aim to later utilise our findings into concrete printing.

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prof. Dr. Henri Hubertus Achten

15116 Ústav modelového projektování

A digital twin is the mapping of a physical twin between hybrid spaces. The lifecycle of digital and physical twins occurs through the concepts of foetal, child, and adult twins. This technology can be used to assist clients and designers with real-time data. The use of digital twin technology in architectural design can be realised at various stages, from design to operation. Designers will be able to gain knowledge of the past, present, and future using this technology. This will reveal possible design scenarios. In this study, a hypothetical scenario is designed, in which designers build a building while already having a digital twin template. To do this, Building Information Modelling is used as a reference model for digital twins, along with the fidelity levels of digital twins and the level of detail-development of BIM. When designers want to design a new project related to their predecessors, they already use the same type of digital twin-building portfolio they can use for their new design. A digital twin will help optimise the new process. Therefore, the digital twin of a building with a similar building type can be used to extract relevant data for the design process.

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prof. Dr. Henri Hubertus Achten

15116 Ústav modelového projektování

A digital twin is a simultaneous digital reflection of object processes and states. Digital twins are usually made of objects that exist in reality or which are very near completion in a design and production process. In our research, we investigate the potential of digital twin technology for early design. Key to the early application of digital twin in design is the role of information and simulation. Since design information is valuable for predicting the future of design, we assume that design will begin to change as digital twin technologies become more and more adaptable, as designers simultaneously have digital twins of the past, present, and future. Digital twin technologies have many capabilities to support the design process at various stages from concept design to the final design. Throughout this process, architects use digital and physical models. Combined with digital twin technology, these models form what we call hybrid prototypes. Estimating that simulation has a vital impact on the design process, we raised the question of what the potential of architectural hybrid prototyping in design processes with digital twin technologies is. Similar to the development of the design through increasingly informed and detailed models, we think that the closest thing to the design process with the digital twin is the so-called foetal, child, and adult digital twin. Based on this classification, we approach the concept of hybrid prototyping and digital twin.

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