An automatic 3D drawing method is presented for reinforced concrete (RC) structures containing cutouts. The method determines all rebar positions in three-dimensional space while preventing bar collisions and ensuring the required concrete cover. Rebar cutouts around pipe penetrations are automatically designed, and additional stiffening reinforcement is arranged to mitigate stress concentrations around openings. The rebar quantities and positions are computed using Visual Basic in accordance with RC design standards, and the results are stored as material data files. The 3D reinforcement layouts are generated in AutoCAD through Visual Basic for Applications. The proposed method is demonstrated using an RC catch basin as a representative example. RC structures are widely used in civil and building engineering, and the proper arrangement and quantity of reinforcement are essential for ensuring structural safety and stability. Although advances in structural analysis have simplified the design process, rebar detailing remains complex and labor-intensive. Drawings are required to verify reinforcement adequacy and to detect potential clashes between adjacent bars. However, such conflicts are difficult to identify in conventional 2D drawings. 3D drawings provide an effective means of addressing these issues. They can also be integrated into VR and AR environments to support construction management and quality control. After construction, the same 3D models are valuable for maintenance and rehabilitation activities. Thus, 3D modeling of RC structures offers benefits throughout the entire service life of a structure. The proposed method provides an efficient approach for generating 3D reinforcement layouts for RC structures.