The automotive engineering process is characterized by a long and complex design process which starts with the first sketches in the preliminary design phase and proceeds to the final detailed CAD and physical models. In this process, every design phase includes different process steps and tasks which are closely interconnected with each other. Therefore the different design stages demand capable Computer Aided Design (CAD) systems which are able to handle the different kinds of design information created and manipulated in the process. Currently in automotive practice, parametric and associative (PA) CAD systems are widely applied in the product development process. Such systems allow design knowledge to be embedded in CAD models by means of rules and formulae. In addition, CAD parts and assemblies can be generated faster and easier by modification of design parameters and therefore there is a possibility to create different CAD model variants which are based on the same CAD model. The four key element of the following work are (a) to identify the problems during the design process with parametric and associative (PA) methods during a three year of study and also the analysis of the literature survey. Furthermore (b) in this study the author will develop and implement a newly developed PA design approach (PARAMASS) in a ―real‖ industrial context. Beside this the following work will (c) discuss the issues which are important during the implementation of the developed PA approach in an industrial surrounding. The last key element (d) is to develop an evaluation approach for the PARAMASS approach during the application in an industrial context. In this case the author will be able to do action research in the industry and get first hand information during the accomplishment of these key elements. This thesis presents the results of a research programme carried out using the design research methodology of Blessing and Chakrabarti, aimed at understanding the difficulties and challenges faced by designers in using PA CAD systems and then developing and evaluating an integrated approach to the creation of PA CAD models in an automotive power train design context. Firstly, this thesis presents a review of the state of the art in PA design methods and approaches and also reviews previous research on the development of methodologies for the construction of PA CAD models. It then presents results of a descriptive study of the use of PA CAD tools and methods in vehicle power train design in an automotive original equipment manufacturer and in companies in its supply chain using questionnaires, interviews, tests and other field studies with a number of practising engineers. This study identified a number of issues faced by designers in the use of PA CAD tools and allowed the requirements for improved methods for the use of PA CAD tools to be formulated and indicators identified for their evaluation. Based on the results of the descriptive study a new integrated parametric associative (PA) approach for the design process of power train components was created in a prescriptive study stage. The approach, called PARAMASS, allows designers to construct and modify models in a methodical way based on three main phases: a specification phase to prepare the relevant parameters and associative relationships, a structuring phase that allows part and assembly structures to be created and a modification phase in which the created parametric and associative information can be modified and changed. The method makes extensive use of predefined structures matrix approaches adapted from the Design Structure Matrix. The prescriptive study phase of the research was followed by a second descriptive study to evaluate and investigate in both a qualitative and quantitative way the changes achieved by the PARAMASS approach. The qualitative evaluation was based on the Goal Question Metric approach and showed that there are advantages related to the reusability aspects like learning, application and acceptance of the developed integrated approach. The quantitative evaluation was based on the Use Case approach and demonstrated good advantages in applying the developed approach, but dependent on the complexity of the created parts and assemblies.

abstract: In geographical locations with hot-arid climates, sun control in buildings is one primary problem to solve for the building envelope design. Today's technological advances in building science bring with them the opportunity to design dynamic façade systems for sun radiation control and daylighting. Although dynamic systems can become an attractive visual element, they can be costly and challenging to maintain for building owners. Alternatively, fixed solar-shading systems can be designed to create dynamism in the façade of the building, while providing similar functionalities for sun control. The work presented in this project focuses on the use of a visual scripting editor for modeling software, Grasshopper, to develop a Solar Control Visual Script that evaluates building envelope surfaces with planar and non-uniform rational basis-spline (NURBS) forms and provides projections for fixed sun control systems. The design platform of Grasshopper allows individuals with no experience or prior computer coding education to build up programming-like capabilities; this feature permits users to discover new design possibilities within flexible frames that can contribute to the overall design being pursued, while also having an environmental response. The Solar Control Visual Script provides minimum sizing geometries that achieve shading in openings at a particular date and time of the year. The model for this method of analysis makes use of three components to derive the appropriate values for the projections of shading geometries: typical meteorological year (TMY) data, irradiation isotropic equations and shading profile angles equations for vertical and tilted surfaces. Providing an automatic visual of generated geometries uncovers the opportunity to test several model forms and reiterates the analysis when modifying control parameters. By employing building science as a set of environmental parameters, the design outcome bears a dynamic form that responds to natural force conditions. The optimized results promote an efficient environmental design solution for sun control as an integral alternative into the building envelope. / Dissertation/Thesis / M.S. Built Environment 2012