Digital human modelling (DHM) systems are used to simulate production processes and analyse the human-machine interaction, particularly at early development stages. Consideration of anthropometric variation is central in DHM simulations due to the necessity of ensuring intended accommodation levels. This paper describes the process of how digital human models are created and defined within the IMMA software. The process begins with the definition of a number of key measurements, which acts as the basis for the definition of several boundary manikins using a confidence ellipsoid methodology. These manikins represents the appropriate confidence region and hence the anthropometric diversity. Key measurements are then entered into regression equations to define the complete set of measurements for each manikin. These measurements are based on the appropriate ISO-standard. Finally, measurements are used to define the size and alignment of each segment in the biomechanical model of the manikin. The manikins are then used to automatically simulate and analyse human-machine interaction.