Karin Forslund

A Framework for Non-nominal Visualization and Perceived Quality Evaluation

Perceived Quality clusters different aspects that influence the customers perception of non-functional quality on a product that are perceive through senses. All together those aspects and the harmony between them reflect the producers ability to control product parameters and thereby also mirror the functional quality of the product. High Perceived Quality can not be added to the product at the end of the developing process. Project prerequisites, system solution, factory capability etc. are criterion to succeed. Therefore, it is important to be able to evaluate Perceived Quality early in the process when product system solutions and architecture are defined, although data maturity is low. This paper presents a comprehensive framework to manage and support evaluation of Perceived Quality aspects in a product development process. The framework is based on an industrial process in combination with recent research within the field. The framework focus on activities that can be performed at different stages in the developing process based on maturity of the CAD or styling data. For example, if the styling data is divided into different components by split-lines it has reached higher level of maturity then styling data that not has been divided. Consequently, the choice of applied method is based on data maturity, regardless phase in the developing process. The framework contain methods based on several different simulation and analysis techniques. Both design methods, Computer Aided Tolerancing and FEA based non-rigid variation simulation are represented in the framework.

Parameters Influencing the Perception of Geometrical Deviations in a Virtual Environment

On car exteriors, geometrical variation, stemming from the manufacturing process, can distort the visible relationships between parts, i.e. the split-lines. In the automotive industry, non-nominal visualization is often implemented as a part of early concept reviews. Visualizing the results from a Computer-Aided Tolerancing analysis in a virtual environment allows to evaluate what deviations will be visible to customers and whether they can have a negative influence on the perceived product quality. The geometry, colors and materials of parts make some split-lines more visually sensitive than others because on them, potential deviations are especially disturbing to the onlooker. Moreover, the visual sensitivity is influenced by the context of product interaction in terms of illumination, reflections and the observer’s viewing angle. These factors need to be taken into account when determining tolerance levels to ensure that an industrial design concept will look good once produced. This paper presents a study of the influence split-line geometry and several visualization parameters have on the ability of test persons to identify geometrical deviations in a number of computer generated images. Additionally, eye-tracking was performed to identify what areas of the split-lines the test persons looked at while performing the task. The results confirm that the included split-lines are not equally sensitive to variation. Further, it is shown that the visualization settings indeed have an influence on the ability to detect variation but that the most sensitive settings differ between combinations of deviations and split-lines.Copyright

Aesthetic consequences of making car exteriors visually robust to geometrical variation

Geometrical variation, stemming from the manufacturing process, can have negative effects on a cars visual quality appearance (VQA) – the quality impression it conveys to a customer visually. Visually robust product design aims to dampen the effects of variation on the customers product experience. Early evaluation of visual robustness can minimise the risk of launching products with poor VQA or for increased costs and late changes during the product realisation process. A method has been developed to evaluate the visual robustness of car exteriors. Design solutions on existing cars were photographed, classified and analysed in order to investigate the relationship between their visual design properties and their visual robustness. In addition, a web-survey performed indicates that visual robustness can be achieved without necessarily compromising the other aesthetic qualities embedded in a design concept. The proposed method enables concept comparison and evaluation regarding visual robustness and can be adapted to various contexts.

Categories of Visual Quality Cues

An industrial design concept can be adapted to manufacture and assembly by striving for visual design properties that are economical and time-efficient to produce according to specifications. One aspect of this is to assess whether the concept will be visually sensitive to distortions in structure, form, colour, gloss and texture. Visual appearance problems are often unrelated to the actual quality or functionality of a product. In the eyes of the customer, they may however serve as intrinsic quality cues, perceptions of quality attributes acquired by observing the product before purchase. Through interviews conducted at an automobile company and a mobile telecom company, factors considered important for the visual quality appearance of their products were identified. These factors are divided into groups, and examples are given. The result is an overview of visual quality appearance aspects, which demonstrates that design for perceived quality can be a trade-off between quality cues as deliberately placed styling features and quality cues stemming from complex assembly variation conditions.

Influence of rigid and non-rigid variation simulations when assessing perceived quality of split-lines

Non-nominal visualisation is used to evaluate how geometrical variation influences the appearance of split-lines between components on a car body. Depending on the simulation method, visualised variation can be represented in an unrealistic manner, which can affect the perception of the result. This paper presents a comparative study in which eye-tracking equipment has been used in order to explore whether the interpretation of variation differs between rigid- and non-rigid-based variation simulations during the evaluation of visualised models. Subjects from the automotive industry were asked to evaluate two virtual models where the same amount of variation was represented by rigid and non-rigid models. Eye tracking was used to record how the subjects performed the assessment. The result shows that there is a significant difference in how simulation results are interpreted using rigid versus non-rigid simulation.

Appearance FMEA: A Method for Appearance Quality Evaluation of Early Design Concepts

For consumer products, early design stages are often concerned with the product’s industrial design, with primary focus on the consumer’s product experience. At this stage, aspects such as manufacturability and robustness are often not thoroughly taken into account. Industrial design concepts not properly suited for manufacture, assembly and process variability can result in final products in which the appearance intent is not satisfactorily realized. This can have a negative impact on the customer’s product quality perception. If such problems are discovered late in the product development process, late design changes and increased project costs may follow. The main difficulty in evaluating perceived quality aspects during industrial design is that the product is still under development. It is not mature enough to enable prediction of the prerequisites for achieving high manufacturing quality. In this paper, we suggest that concepts instead could be evaluated as far as the intrinsic tendency of the product appearance to support manufacturing variation and other noise factors. This is addressed through the concept of visual robustness: the ability of a product’s visual appearance to stimulate the same product experience despite variety in its visual design properties. Here, a method is suggested based on the Failure Modes and Effects Analysis (FMEA). The method follows a structured procedure for addressing appearance issues.Copyright