This paper is about describing and analysing modelling practices in automotive industry and electronics design. Based on ethnographic observations in modelling sessions in three case studies, we tried to describe the modelling scope in real work environments. This helped to identify problem areas or areas of change, articulation work in decision making activities during modelling, models as shared objects and issues of accessing the models by different communities of practice. The focus of our investigations was on a specific modelling environment called Active Knowledge Modelling (AKM).