## 2 Materials and Methods
### Evaluation of the Efficiency of AutoCAD and AutoCAD Mechanical
#### 2.1.1 Predefined Drawing Tasks  
* Screw connection. Figure 1 represents a technical drawing of a flanged screw connection, depicted through orthographic views, including a top view and sectional view (A-A). It follows standard engineering drawing conventions to illustrate the assembly, fastening, and internal structure of the connection. The top view (left) contains a circular flange geometry with four equally positioned bolt holes for securing the assembly. There is bored hole or shaft clearance, for fluid flow, alignment, or mechanical coupling. The bolted joint assembly is detailed in the sectional view A-A, including hexagonal bolts, washers, and nuts securing the flange. This flange connection drawing serves a critical role in piping systems, mechanical assemblies, and structural supports. Designed with a bolted joint configuration, it ensures secure fastening while minimizing the risk of loosening under mechanical loads. The sectional view provides a detailed representation of internal features, offering machinists and engineers a clear understanding of otherwise hidden components essential for precise fabrication and assembly. * Shaft assembly. This task involves the creation of an engineering drawing of a shaft assembly, represented through two orthographic projections: a side view and a front view (Figure 2). The drawing follows established technical drafting standards, incorporating centerlines and sectional details to enhance clarity and precision. Figure 1: Screw connection. Shaft drawings are essential in the design and manufacturing of rotary machinery, transmission systems, and mechanical couplings. The inclusion of sectional views and threading details highlights key interfaces where the shaft interacts with other mechanical components. By using orthographic projection, sectional views, and centerlines, the drawing ensures accuracy in fabrication and assembly, allowing for seamless integration within complex mechanical systems. * Hidden geometry. Figure 3 represents a detailed top view of a mechanical flange assembly, with extensive use of hidden lines and centerline references. It depicts a flanged connection with bolted holes, which could be part of a pipe fitting, rotary machine, or structural component. Hidden line drawings like this are essential in mechanical and structural engineering, providing detailed internal geometries without requiring a sectional view. This type of drawing is common in flange couplings, rotary equipment housings, and pressure vessel connections. The inclusion of hidden lines and reference geometry focuses on precise machining, assembly, and mechanical fit. * Enlarged view. This case presents a sectional view with an enlarged detail of a flanged mechanical component (Figure 4). The illustration consists of two distinct views. The enlarged sectional view on the left, labeled \"B (2:1)\", is displayed at twice the original size to enhance the visibility of intricate details. The main sectional view on the right, labeled \"B\", provides the full cross-sectional profile of the component. A green circular highlight marks the specific area of focus for the enlarged view, ensuring a detailed examination of critical features. Figure 3: Hidden geometry. Figure 2: Shaft assembly. Enlarged views play a crucial role in technical drawings, as they emphasize fine details, machining tolerances, and precision features that might not be clearly visible at the standard scale. They are particularly valuable for components such as flanges, couplings, rotating machinery, and precision mechanical parts, where accurate detailing is essential for manufacturing and assembly. * Dimensioned and annotated machined shaft. Figure 5 presents a fully dimensioned and annotated technical drawing of a machined shaft, incorporating geometric dimensioning and tolerancing, machining specifications, and manufacturing details. Adhering to established engineering drawing standards, this illustration ensures manufacturability, precision, and quality control.