This paper focuses on Digital Human Modeling [DHM], the ergonomic analysis of heavy truck drivers using 3D software, and Digital Twin, an emerging technology. A systematic literature review was conducted to understand DHM and Digital Twin and its current application. To demonstrate the application of DHM, a 3D software - RAMSIS was used to perform an ergonomic analysis of a heavy truck driver. DHM is a technique used for creating a virtual environment of a product to simulate human interaction with it. In contrast, Digital Twin is a virtual representation of a real device across its lifecycle that can be understood, learned, and reasoned with real-time data from the field. A brief analysis of the current development of these technologies, their application, and their limitations is documented in the literature review. To show a significant application of DHM an advanced ergonomics analysis for comfort, reachability, visibility obstruction, and potential reflection during nighttime is carried out for a heavy truck driver using the RAMSIS software. To optimize the driver’s position and reduce the discomfort level on the body parts, several adjustments in the virtual environment were carried out and the results were documented.