What are copies of mechanical or other types of technical drawings called?

The term used for copies of mechanical or other types of technical drawings is "blueprints." Blueprints are generally recognized as the standardized methodology for reproducing architectural and engineering drawings, allowing for detailed representation of designs in a highly accurate and accessible format. Historically, blueprints were produced using a specific chemical process that resulted in white lines or images on a blue background, which is how the name originated.

Blueprints serve a critical function in construction and manufacturing by providing precise specifications and measurements that guide the work of builders and engineers. This accuracy is essential for ensuring that structures or products are built according to the intended design and safety standards.

Other options describe different forms of visual representation. Drafts refer to preliminary versions of plans or drawings that are subject to modifications. Sketches are informal drawings that capture general forms or ideas rather than precise details. Plans can refer broadly to any type of schematic or diagram, encompassing blueprints but also including various types of documentation. However, blueprints specifically denote the reproductions of detailed technical drawings, making it the most appropriate choice for the question.