The objective evaluation of occupant comfort is a complex task where numerous aspects such as posture, pressure distribution, internal tissue loads, handling of steering wheel or gear shift have to be taken into consideration. Currently the standard evaluation procedures are hardware tests with human subjects, who are sensitive to all these aspects. However, the reproducibility of subjective tests for the comparison of design variants is a questionable issue and the costs for each test cycle with new prototypes are very high.As an alternative, numerical approaches using human body models such as AnyBody , CASIMIR  or RAMSIS  are applied. Here the issue of reproducibility does not exist and only little effort is required to investigate new setups. However, the disadvantage is that each approach focuses only on one specific aspect of occupant comfort, while in reality the emotions of the occupant are always a combination of all impressions. Furthermore, these kinds of numerical approaches can only provide mechanical quantities like seat pressure or joint angles. Defining the relation between these objective values and subjective rankings and defining optimization targets is a great challenge.For a comprehensive virtual comfort evaluation, the interaction of the different numerical approaches is essential. This is the goal of the research project UDASim , funded by the German government. Here the transfer of the posture between the human body models was a first goal to ensure consistency between the investigated setups. A second step was an iterative simulation procedure. In this procedure, a CAD-based setup is combined with a mechanical setup, which allows the simultaneous assessment of packaging and seat design.