# Enhancing Furniture Manufacturing with 3D Scanning
## 4 Results  
### Case Study No. 1  
The undertaking described as c'ase study no. 1' was conducted by the Faculty of Mechanical Engineering at the University of Sarajevo, collaborating with Bosnia and Herzegovina's Alpha Corporation as the producer. [PERSON], an Italian furniture designer, was author of the design of the analyzed piece of furniture.  
The design process began with creating initial concept models in real size by hand. These physical models were then brought into the digital realm using 3D scanning technology. These scan data, initially in the form of a point cloud (STL 3D model), were the foundation for creating CAD 3D models suitable for manufacturing. Figure 8 illustrates a prototype of a product designer's lounge chair undergoing 3D scanning.  
In the first step, the product designer created a digital design. In the second step, the mechanical engineers used that digital design to produce the first prototype. After a visual and practical examination of the first prototype, the designer was not satisfied with the chair's shape, look, ergonomics, and practical aspects, so he used hand tools for grinding and polishing to create a new, modified prototype. The problem is that the latest prototype did not match the 3D CAD models, so it was impossible to manufacture more chairs with the modified design. It was necessary to 3D scan the new design and use 3D-scanned models to create new CAD models ready for manufacturing.  
A mainly blended command was used for chair legs, combining cross-sectional sketches and mirroring another side. The CAD modeling is shown in Figure 9; the same method was used for the squat part of the legs.  
The 3D modeling began with standard surface modeling techniques applied to the raw scanned raw data (point cloud). This involved creating multiple splines across the scanned surface. Next, a sweep command was used to generate the initial surface model. This surface was then refined by cutting it along the edges of the scanned data. Finally, a thickness of 10 mm was applied to create the solid 3D CAD model (Figure 10). This lounge chair comprises legs, a seat, and a separate part to rest the legs. The final form after manufacturing is shown in Figure 11. In this case, the scanning time of all three parts takes around 2 h, the processing of all scans for all three parts takes around 5 h, and 3D modeling (reverse engineering) takes an additional 6 h.  
Figure 7: Analysis of the dimensional accuracy of the created CAD models.  
Figure 8: Three-dimensional scan of the parts of the lounge chair.  
Figure 9: CAD modeling of the lounge chair legs.  
Figure 11: Manufactured lounge chair (**right**) with footrest (**left**) [28].  
Figure 10: CAD modeling of the lounge chair seat.  
The analyses of the dimensional precision for the legs and seat are shown in Figure 12. The dimensional accuracy analysis is carried out only on one side of the chair because one side is scanned in 3D and another is created using the mirror command during 3D modeling (Figure 9).  
A dimensional analysis of the lounge chair seat (Figure 13) confirms deviations well below 1 mm, which is well within the acceptable tolerances for furniture manufacturing. It is important to note that for laminated wood components pressed and deformed like this seat, achieving extremely high dimensional accuracy throughout the entire structure might not be necessary. The production process can introduce minor cracks and delaminations (Figure 14). These imperfections are acceptable in this case, as the final product will be upholstered with soft material, effectively hiding them. In such components, dimensional deviations of up to several millimeters might be accepted.