A digital human model simulation (DHMS) system is a useful tool to design ergonomic products and evaluate usability of different products. This study developed a systematic method to create dynamic motions of digital human models in RAMSIS software, and applied the method to create ingress and egress motions in a vehicle as a case study. For this, a motion capture system is used to collect the trajectory data of markers attached to a user’s body. The manikin, a digital human model in RAMSIS, is produced by user’s anthropometric data. The trajectory data of joint points of the manikin are used to create dynamic motions of the manikin, that are produced by the actor and the character that are digital human models in another DHMS system (MotionBuilder). As a case study, the participants to which thirty seven markers were attached naturally entered and exited the car mockup in the experiment. Ingress and egress motions of each manikin were created by the systematic method developed.