A skeleton modelling approach for aluminium profile design: Licentiate thesis

In this work we present a modelling approach for the creation of two dimensional geometric components. In this approach, the abstract shape of a component is represented by skeleton lines that designers use when sketching components in the early phases of design. The skeleton line representation is afterwards embodied into the contour model by means of skeleton modelling operations. The approach was applied to an aluminium profile (aluminium extrusion) design. The skeleton line representation is analogous to the traditional pen and paper representation that designers use when sketching the shape of the profile. The abstract sketches, which may not be understandable to others, can be refined into concrete models by means of the modelling operations. Using the proposed modelling approach, there is no need for separation of the creative sketching phase from the detail drafting phase. The designer could begin the work at the computer in the phase of design when the structure and the shape is not yet embodied. For the systematic design for aluminium profiles, we developed a methodology from general engineering design theories. It was concluded that our modelling approach speeds up the designing of profiles. The proposed modelling approach was put to the test by choosing a sample for client designed aluminium profiles. It was concluded that the approach was suitable for representing 81 per cent of the studied profiles. The modelling system uses modified offset techniques and other geometric modelling methods. The modelling techniques were implemented in a commercial CAD system using object oriented programming methods.