The invention relates to a method and a computer-aided modelling system for creating a technical drawing from at least two modelled 3D bodies that collide with one another. In a first step, one or more of the regions of the 3D bodies that are affected by the collision are selected. In a second step, a group of colliding faces of the selected regions of the two or more 3D bodies are combined to form a respective collision group and a technical drawing of the two or more colliding modelled 3D bodies is produced. A 2D edge or its associated boundary of a face that belongs to a collision group is treated by masking the other faces that are associated with the same collision group.