Evaluating the Effects of Variation on Product Appearance through Visual Robustness
Doktorsavhandling, 2011

For consumer products where the product appearance plays an important role in meeting expectations, the visible effects of manufacturing variation can have a negative influence on the product experience. A concomitant of mass production is that no manufactured units are exactly identical, as a result of variation. However, reducing variation is often associated with increased manufacturing and development costs. The main question addressed in this thesis is therefore how to evaluate the effects of variation on product appearance and perceived quality. The product property controlling these effects is referred to as visual robustness. Visual robustness is the ability of a product to stimulate the same visual experience as the nominal product, despite small variations. It depends only on the product appearance in terms of form and colours of visible parts. A key suggestion is therefore that product appearance should be made robust to deviations, thereby dampening the visual consequences of variation. Particular focus is set on visual robustness to geometrical manufacturing variation, visible in the split-lines between parts. However, a product can be visually robust to different types of deviations, such as colour deviations occurring during manufacture, or to the effects of ageing or wear. As visual robustness controls the effects of deviations on the perceived product quality, special attention is given to this relationship. Different types of aspects that influence the perceived product quality have been identified and categorized. The main result of this thesis is a framework describing visual robustness and its relation to the perceived product quality. To explain what makes products visually robust to geometrical variation, the concepts of visual references and amplifying factors are introduced. Two user studies are performed, exemplifying phenomena related to visual robustness, and two prescriptive methods for comparing the visual robustness of early design concepts are presented. The Visual Sensitivity Analysis aims to quantify visual robustness by looking at the amount of visual references between parts in an assembly. The Appearance FMEA is a procedure for enabling detection of different kinds of appearance imperfections, and promotes considerations of visual robustness in early design stages. A number of studies have been also performed in order to describe how aspects related to visual robustness are handled in Swedish industry today.

product experience

visual quality appearance

visual sensitivity

optical quality

industrial design

perceived quality


robust design

non-nominal visualization

geometrical variation

visual robustness

Virtual Development Laboratory, Hörsalsvägen 7A, Göteborg
Opponent: MIchael Tovey


Karin Nordvall

Chalmers, Produkt- och produktionsutveckling, Produktutveckling

Categories of Visual Quality Cues

Proceedings of the ASME 2007 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, September 4-7, Las Vegas, Nevada,; Vol. 4(2007)p. 881-889

Paper i proceeding

Investigating the Role of Simulation for Robust Plastic Design

Proceedings of NordDesign2010 International Conference on Methods and Tools for Product and Production Development,; Vol. 1(2010)p. 185-194

Paper i proceeding

Optical quality as a product attribute - a descriptive study from the automotive industry

Proceedings of NordDesign 2008, August 21-23, Tallinn, Estonia,; (2008)p. 79-88

Paper i proceeding

Parameters Influencing the Perception of Geometrical Deviations in a Virtual Environment

Proceedings of the ASME 2011 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, August 28-31, Washington, DC,; Vol. 9(2011)p. 1105-1114

Paper i proceeding

Appearance FMEA - a Method for Appearance Quality Evaluation of Early Design Concepts

2009 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, DETC2009; San Diego, CA; United States; 30 August 2009 through 2 September 2009,; Vol. 8(2009)p. 217-225

Paper i proceeding

The Effects of Geometrical Variation on Perceived Quality - A Close Look at the Concept of Visual Robustness

Proceedings of the 11th International Conference on Computer Aided Tolerancing, March 26-27, Annecy, France,; (2009)

Paper i proceeding


Produktionsteknik, arbetsvetenskap och ergonomi

Övrig annan teknik


Hållbar utveckling

Innovation och entreprenörskap





Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie

Virtual Development Laboratory, Hörsalsvägen 7A, Göteborg

Opponent: MIchael Tovey