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Sketching and Concept Development
Xiao Zhang
School of Interactive Arts and Technology
Simon Fraser University
Surrey, BC, Canada
xza57@sfu.ca
Ron Wakkary
School of Interactive Arts and Technology
Simon Fraser University
Surrey, BC, Canada
rwakkary@sfu.ca
ABSTRACT
In this paper, first, I explore how sketching helps a designer
to develop ideas by applying Schön’s model of design.
Then I use Activity Theory as a theoretical lens and an
analytical tool to recognize each components of the
sketching activity system and to examine the relations of
designer and object as mediated by the primary
components. And I also discuss two tensions of this system
in the context of product concept design stage. Based on the
analysis results, finally, I propose two possible solutions
toward a problem, how sketching can affect concept
development effectively in a design group.
Author Keywords
Sketching, concept development, activity theory, reflectionin-action.
ACM Classification Keywords
H5.m. Information interfaces and presentation (e.g., HCI):
Miscellaneous.
INTRODUCTION
In the field of architectural design and industrial design,
sketching has played a key role in the conceptual design
stage particularly. Representing early designs by freehand
drawings can be seen as far back as the early 15th century
[16]. Sketching and conceptual designing are two
inseparable acts for most architects and industrial designers
possibly, because sketches are the tools which they use to
progress their design ideas. Design sketches are different
from ‘drawing from the object’. Whether or not they are
intended as faithful copies, drawings done by artists from a
model, show accidental features that are typically observed,
not invented. Sketches are not drawings of something that
already exists. Instead the designer is involved in a process
of attempting to give external definition to an imagined, or
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only half imagined suggestion for a design idea. In the last
30 years, Design researchers have studied why sketches
have been an efficient medium for conceptual designing.
One of the earliest finding is that sketches store design
solutions and seem to be essential for recognizing conflicts
and possibilities [1]. Some studies proposed that ambiguity
is one of the key factors of sketches [13], because it allows
the seeing of new possibilities in the representations, in
other words re-interpretations [12, 27, 28]. Sketches also
seem to be essential for revising and refining ideas,
generating concepts and facilitating problem solving [7].
The importance of external representations has been
emphasized in other problem solving domains [3, 14, 20]
for facilitating cognitive mechanisms. But despite the
extensive literature on the functions of sketch in the
conceptual design stage, the sketching behavior has not
been sufficiently considered. In fact, the function and
nature of sketches is inseparable from the process of
sketching. Research on sketching not only supplies
designers with an opportunity of reflection on their
sketching activity, but also permits the theorist to catch a
few stop-motion glimpses of the flow of creation. This
research takes Schön’s model of design and Activity
Theory as a theoretical framework to analyze sketching in
the field of industrial design to recognize how sketching
helps a designer to develop ideas and how sketching can
affect concept (in this paper, it means form/shape)
development effectively in a design group.
The rest of this paper is organized as follows: first, I will
present an overview of Schön's model of design and then
use it to analyze the sketching process to answer the first
question. Next, main concepts and general ideas of Activity
Theory will be summarized. Based on these concepts, each
component of sketching activity system will be recognized
and two tensions of this system will be discussed. In the
following section, I will propose two possible solutions to
resolve the second question based on both Activity Theory
and Schön's model of design. And the final part ends the
paper with the evaluation of Schön's model of design and
Activity Theory.
DESIGN AS A REFLECTIVE CONVERSATION WITH THE
SITUATION

In his best known book, “The Reflective Practitioner”,
Schön sought an account of the nature of professional
activity based on the common elements of the practices he
had observed. Schön rejected a theory of technical
rationality that distinguishes professionals by the extent of
their “book knowledge” and developed an alternate theory
of the professional as reflective practitioner. A reflective
practitioner is a practitioner whose knowing is not only
rational and cognitive but also embodied in action and for
whom reflection is critical to practice.
Schön discerned three main levels of professional knowing:
• Knowing-in-action — it refers to the kinds of
knowledge we can only reveal in the way we carry
out tasks and approach problems. “The knowing is
in the action. It is revealed by the skilful execution
of the performance – we are characteristically
unable to make it verbally explicit [26].”
• Reflection-in-action — The examination, analysis and
experimentation needed during the process addressing
singular situations; often making the criteria and
knowledge of action explicit and moreover often shifting
from problem solution to problem formulation.
• Reflection-on-action — the retrospective
contemplation of practice undertaken in order to
uncover the knowledge used in practical situations,
by analyzing and interpreting the information
recalled.
Schön also sought a way to define a design process that was
common to the many professional fields of design and took
special interest in how this process may be learned. He
described that there was a great deal of complexity in the
process of design, because the totality of an artifact, system,
or situation includes many elements: materials, a sense of
purposes and constraints as the designer sees them, and the
designer's sense of the people who will eventually use the
artifact resulting from the design process. Also, often, the
thing a designer makes initially is a representation, a plan, a
program, or an image to be constructed by other people.
Many of the relevant variables cannot be represented in a
model; this limitation makes the design process inherently
complex. In addition, the design process is complex in the
specific sense that, whenever a designer makes a move,
he/she gets results that are not just the ones that he/she
intend. That is, he/she cannot make a move that has only
the consequences that he/she intends. And any move has
side effects. “When this happens, the designer may take
account of the unintended changes he has made in the
situation by forming new appreciations and understandings
and by making new moves. He shapes the situation, in
accordance with his initial appreciation of it, the situation
“talks back”, and he responds to the situation's back-talk
[26].” In order to illustrate this complicated process, Schön
used an example of architectural designing in a design
studio, presented audio-taped protocols from teachinglearning
sessions and studied the way that the instructor
made suggestions about a student's design as he gestured
and drew on a sheet of tracing paper over her work. Schön
described the instructor’s design behavior, the ensuing
inquiry, as a global experiment and a reflection-in-action
process. So the whole process of the instructor’s design
behavior has been beautifully and famously described as
“design as a reflective conversation with the situation [26]”.
And this process can be separated into four steps which
happen smoothly: naming the relevant factors in the
situation, framing a problem in a certain way, making
moves toward a solution and evaluating those moves. The
designer functions as both a creator developing a solution
and an experimenter trying to understand the situation he is
creating in this process. As such, Schön’s model accounts
for the dynamic, cyclic, unfolding and unpredictably nature
of design. In fact, this model is based on two arguments.
First, framing a problem consists of ‘knowing in action’
(i.e. design experience, design knowledge, skills and
judgments), which cannot be accounted for in mere
scientific terms. Second, knowing in action helps the
designer to construct a new way of setting the problem – a
new frame, which he imposes on the situation.
How Sketching Helps A Designer Develop Ideas
Schön viewed design as a reflective conversation with the
situation, where the designer interacted with the situation in
the reflection-in-action process being distinguished from
reflection-on-action. Just as the teaching-learning example
Schön gave, the sketching process in the concept design
stage of industrial design is also a reflection-in-action
process in which a designer reflects both on the shape
he/she is representing through his/her drawing and on
his/her previous way of thinking about the situation in the
sketch. A reflective conversation happens between the
designer and his/her sketch, the shapes he/she draws on
paper. That is, when the emerging and changing shape
“talks back” to a designer, he/she simultaneously responds
to the shape by transforming the shape in his/her mind and
representing the changed shape through his/her hand and
pen, such as adding a circle or thickening a line. In fact, in
the context of sketching, shape’s “talks back” is designer’s
recognition of this shape. During the recognition process,
designers selectively recognize certain shapes that they can
see by concentrating their visual searchlight. So the
recognized shapes are not identical copies of the shapes on
the paper. The conversation between a designer and his/her
sketch is illustrated in Figure1.
Based on the analysis above, I describe sketching activity as
a “recognizing--- transforming --- representing” process. By
applying the recognizing capacity, designers could see
meaningful shapes from ambiguous sketches. Then, in the
transformation process, the recognized shapes are
transformed not only to satisfy design functions [27] but
also to consider the previous shapes [13]. In the following
process, the transformed shapes are depicted on the paper
through designers moving a pen. In the whole process,

shapes are continually changed and thus the design ideas
are developed. Therefore, from the microscopic perspective,
sketching process is illustrated in Figure 2.
Figure 1. Reflective conversation between a designer and
his sketch
After our design team’s research which considers the kiosk
design from different perspectives, like Accessibility and
Ergonomics, we determined three design ideas: Fixed Wall
Mounted kiosk, Adjustable kiosk and Sculpture –like kiosk.
As for the idea of Sculpture –like kiosk, I had two forms in
my mind initially. As illustrated in Figure 5, although they
are similar to some extents, they can be developed and
transformed into other shapes. Moreover, during the
sketching process, some shapes are generated by combining
more than one previous concept, like concept f, g, m, i, k
(see Figure 4). Therefore, various concepts for one design
idea come from:
• Lateral transformations: movement from one
concept to a slightly different one.
• Vertical transformations: movement from one
concept to a more detailed and exacting version of
the same concept.
• Composite transformations: movement from more
than one concept to a different one.
Figure 2. Figure captions should be centered and
placed below the figure
• Design image (ID): an imagined, or only half
imagined shape for a design idea.
• Sketch image (IS): the shapes which are depicted
on the paper through designers moving a pen.
• Recognized image (IR): the shapes in designers’
mind which are recognized from IS.
• Transformed image (IT): the shapes in designers’
mind which are transformed IR by additions,
deletions and modifications.
Figure 3. One cycle in sketching process
In essence, these four kinds of images are different from
each other. Because first of all the image (IR) of the sketch
that designer have recognized through their visual
perception is not what the sketch (IS) originally intends to
present; Then, designers design and redesign in their mind
to generate various design concepts (IT); And most
importantly, in the actual representing phase, due to lack of
drawing skills, designers may not draw the shapes like their
wishes, which may lead to a completely new image。
From the analysis above, sketching, which begins with an
imagined, or only half imagined shape in a designer’s mind,
is a dynamic, experimental, unpredictable and iterated
process until the designer is satisfied with the final shapes.
And each cycle has three processes (see Figure 3). However,
in reality (see Figure 4), the situation of the sketching
process is more complicated than the model (see Figure 2),
because for one design idea, a designer may have several
design images in his/her mind. Take a design project as an
example, an information kiosk design for an art museum.
Figure 4. One design project of mine

Figure 5. Two concepts from the same idea
Based on the designing ability of designers, their capacity
of recognition, transformation and representation will also
be different (see Figure 6). Liu [22] proposed that people
from different backgrounds would notice different levels of
shapes; however, only people who have certain design
ability would recognize subshapes, which are hidden in
shapes. For instance in Figure 7, not all designers pay
attention to the three subshapes: U shape on the top surface;
the top surface is convex; the front surface is not flat. In
comparison, the transformation process is determined by
design experience and the associating capability of
designers. And a designer’s drawing skill affects the
representation outcome. Thus, different designers who see
the same shape will produce different quantity and quality
distinct sketches.
Figure 6.
Figure 7. Recognizing subshapes
ACTIVITY THEORY
Activity Theory is a philosophical and cross disciplinary
framework for the study of different forms of human
practices as development progresses, with both individual
and social levels interlinked at the same time [17]. The term
“Activity Theory” emerged between 1920 and 1930, in the
Soviet Historic-Cultural School of Psychology [18, 24].
Activity Theory has evolved through three generations of
research. When discussing activity, activity theorists are not
simply concerned with “doing” as a disembodied action but
are referring to “doing in order to transform something”,
with the focus on the contextualized activity of the system
as a whole [9, 10, 19]. Activity Theory is formed by a set of
principles that constitutes a general conceptual system. The
basic principles of Activity Theory are [18, 24]:
• Principles of the unit between activity and
consciousness. It is considered the fundamental
principle of Activity Theory, where activity and
consciousness are treated in an integrated way.
The consciousness means the human mind like a
whole, and activity means the human interaction
with its objective reality. This principle states that
the human mind emerges and exists like a special
component of the human interaction with its
environment [18]. The mind is a special organ that
appears in the evolution process to help organisms
to survive. So, it can be analyzed and understood
only within the human activity context.
• Principle of the object orientation. This principle
focuses on the approach of Activity Theory for the
environment where the human being interacts.
Human beings leave in an environment that is
very important for them. This environment
consists of entities that combine all kinds of
objective features, including those culturally
determined, which influence the ways persons act
over those entities.
• Principles of the hierarchical structure of activity.
Activity Theory differentiates the human
procedures in several levels (activity, action and
operation), taking into account the objectives to
which these procedures are oriented. The
importance of that distinction is determined by the
ecological attitude from Activity Theory. In a real
situation, this distinction is frequently necessary
to preview the human behavior. So, this
distinction is very important to make the
differentiation among motives, goals and
conditions that are associated.
• Principle of the internalization-externalization.
This principle describes the basic mechanisms
about the mental processes source. It states that
mental processes are derived from external actions
through the way of the internalization [18].
Internalization is the information absorption
process (in several ways) achieved by human
mind, which derives from the contact with the
environment where the person is located. The
externalization is the process contraire to
internalization, manifested through acts, in such a
way they can be verified and fixed, if necessary.
• Principle of the mediation. The human activity is
mediated by several tools, both external and

internal. The tools are “vehicles” of the social
experience and cultural knowledge.
• Principle of the development. According to
Activity Theory, to understand a phenomenon
means to know how it is developed by itself until
its current shape, because it changes by the time.
Understanding these changes can help to
understanding its current state.
These principles are not isolated ideas, they are closely
connected. The nature of Activity Theory is manifested in
this set of principles.
Figure 8 portrays a pictorial representation of a generic
activity system as conceptualized by Engeström [9, 10].
The subject is the agent that acts over an object. Object can
be raw materials, conceptual understandings, or even
problem spaces, “at which the activity is directed and which
is molded or transformed into outcomes with the help of
physical and symbolic, external and internal tools [10]”.
The community of a system refers to those individuals,
groups, or both who share the same general objects, and are
defined by their division of labor and shared norms and
expectations. Specifically, divisions of labor can run
horizontally as tasks are spread across members of the
community with equal status, and vertically as tasks are
distributed up and down divisions of power. Last, activity
systems are somewhat constrained by the formal, informal,
and technical rules, norms, and conventions of the
community.
The components of activity systems are not static
components existing in isolation from each other but are
dynamic and continuously interact with the other
components through which they define the activity system
as a whole. From an Activity Theory perspective, an
examination of any phenomenon must consider the
dynamics among all these components. In addition to the
interactions of an activity system of a particular time and
space, it is important to note that an activity system is made
up of nested activities and actions all of which could be
conceived of as separate activity systems or other instances
of the same system depending on one’s perspective. For
example, although the computer may serve as a tool in a
current action, at an earlier time this computer may have
been an object or an outcome in what may be conceived as
a previous action of the same activity system or even as a
different activity system.
A focus of Activity Theory is on how participants transform
objects, and how the various system components mediate
this transformation. With respect to the role of computers,
for example, activity theorists are concerned with how these
tools mediate the relations between subject and object.
Therefore, it is not simply the human–computer (subject–
tool) interaction that is fundamental to understand, but the
subject–object interactions as mediated by the computer
that become crucial [19]. This perspective expands the unit
of analysis from the mind of the individual (as in traditional
cognitive research) or from the human–computer
interaction (as in traditional human–computer interaction
research) [5, 6], to the entire activity system [4]. Activity
systems are characterized by their internal contradictions [9,
10, 21]. These contradictions are best understood as
tensions among the components of the activity system.
Tensions are critical to understanding what motivates
particular actions and in understanding the evolution of a
system more generally.
In summary, an examination of an activity system must
address all these components, as well as the inherent
tensions, as a unified system.
Figure 8. The basic structure of human activity
How Sketching Can Affect Concept Development
Effectively in a Design Group
In this section, first, I will present an overview of concept
design stage in industrial design which will provide me a
background to consider the problem, how sketching can
affect the concept development effectively in a design
group. Second, I will use activity theory as my theoretical
lens and analytical tool to recognize each components of a
sketching activity system and to examine the relations of
designer and object as mediated by the primary components.
Engeström’s triangle [9] is used to define the component
structure of sketching activity based on different design
stage. Then, according to my own design experience and
some research on collaborative design, two inherent
tensions in the sketching activity system will be identified.
Finally, I will propose solutions to resolved the tensions and
thus give suggestions towards the problem.
An Overview of Concept Design Stage in Industrial Design
New Industrial Product Development Process is a series of
phases that projects generally take in progressing from
initial product idea generation through stable production.
The first two stages are idea generation and concept design.
Idea generation activity lays the groundwork for entry into
the Product Development Process. Prior to starting the
concept design phase, information on market development
(competitive offerings, etc.), customer satisfaction
feedback, technology development and business strategy is
helpful for generating ideas for a new product. Wherever a
new product idea is generated in the ideation process, the
product concept design phase begins when an idea or new

product innovation is documented and initially reviewed by
management. If management commits to supporting the
definition and evaluation of the product ideas for possible
funding, it enters the product concept design phase. In the
concept design stage, several industrial designers work
collectively with other participants who may come from
management, marking, engineer, the software department
as well as stakeholders or users. The staff structure of
concept design group varies, according to different project
and different company. The main goal of this phrase is
developing product ideas into different concepts----in other
words, forms. And concepts are often showed through
sketches, because sketching is a low-cost, fast and flexible
way. As is shown in Figure 9, concept design stage is an
iterative, repeated divergent and convergent process [23]. In
a divergent step, a range of concepts is generated, followed
by a convergent step in which evaluation and selection of
these are made. Along with the increase of the iterative
times, detailed concepts will be provided.
Figure 11. Structure of sketching activity
Subject: people who involve in the sketching activity in the
concept design stage. Often, more than one designer work
on sketching, because a principal aim of conceptual design
is to generate promising concepts. To achieve this aim,
generating a wide range of concepts is important, so that
valuable concepts are not overlooked.
Figure 9. Concept design stage which is a repeated divergent
and convergent process
Activity Theory as Analytical Tool
According to the overview of concept design stage, there
are three main activities: sketching, evaluating and
choosing. They are driven by different motives and are
realized through a sequence of actions. But this paper only
develops the systemic model of sketching. Figure 10 is the
sketching activity system at the first design stage and
sketching activity is decomposed into actions: recognizing,
transforming and representing (see Figure 11).
Object: ideas which generated at the first phase of the new
industrial product development process.
Tool: drawing tools and design knowledge which help
designers to transform design ideas into concepts.
In industrial design sketches, the most frequently used
drawing tools are pencil, pen and marker.
• Pencil includes regular pencil and colored pencil.
This kind of tool allows user to draw smooth, fluid
and soft flowing lines. The richness of layers of
lines brings the sketch lifelikeness and reality.
Designers can adjust the angle, pressure and
number of lines to control the thickness, tone and
opacity of their sketches. In addition, Pencil
drawings can be easily erased and corrected which
would be appropriate for drawing curves and
products that have smooth surfaces (see Figure
12).
Figure 12. Pencil as a tool
Figure 10.
• Pen includes pen, signature pen and ball-point pen.
These tools can draw succinct and sprightly thin
lines that have strong contrast and expressiveness,

ut they are hard to modify. Pens are good for
depicting details and more delicate sketches and
are usually adopting the method of single line
tracing. Final design sketches are mostly pen
sketches because they are high contrasted, hardly
blurred and long lasting (see Figure 13).
Figure 13. Pen and ball-point pen as tools
• Markers are usually used along with pen or pencil.
They have unique colors, various shapes and
thickness of strokes that can change the density of
lines and bring the sketch to life. Different lines
can be drew depend on different pressure, speed,
tone, dryness, thickness and density of the use of
strokes and they can quickly express shapes,
surfaces, textures and colors of the product (see
Figure 14).
Outcome:sketches which come from object, design ideas.
Sketch is different from drawing. Industrial design sketch
has some distinct characteristics which are used to help
designers to express their ideas about the form. An
examination by a research team of a collection of
automotive sketches revealed these characteristics. The
study showed that there were a number of different ways in
which lines were used. They tend to be of the following
types [29] (see Figure 15):
• Form lines: these are typically the lines along shutlines,
or car body panel edges, which are the key
form descriptors. They are assumed to be of
primary importance in delineating the shape that
the designer intends for the design.
• Crown lines: these are not ‘real’ lines in the design
but indicate the crown of a curve, or extent of a
contour.
• Area lines: these are lines which simply define an
area. This may be a physically separate component
(eg; a numberplate) or a cartoon-like depiction of
the edge of a shadow.
The other key components of sketches are shading and
colour. Both are used less often in initial concept sketches,
which may consist simply of lines. In the same study
mentioned above, the designers observed rendered almost
exclusively in lines when in the early stages of concept
development. When shade is used, it is intended to enhance
the three dimensional definition of the form, usually at later
concept design stage. Interestingly, the students observed in
this study made much greater use of shading and colour
than professional designers. Possibly the fact that their
sketches were intended to communicate with their assessors
has something to do with this, or it may be simply that the
professionals’ greater fluency allows them to suggest form
quickly without resorting to shading.
Figure 14. Marker and pen as tools
• Product concept design requires many design
factors to be considered simultaneously and
involves several fields of knowledge. It mainly
includes designers’ experiences about the form,
structure, craftsmanship, materials and color of the
industrial product as well as their skills of design
representation and the knowledge of background
information of the product they are designing.
Figure 15. Form line, area line and crown line
Community:industrial designers and any individual who
has a legitimate say in the process, whose words, proposals,
claims and supplications matter and contribute to the final
form of the product I consider a participant in community.

The core group in concept design stage is of a particular
sort. These participants are, for the most part, members of a
firm – a corporate entity whose purpose is production for
profit. They share a common object, namely to transform
design ideas into a concept which will contribute to a
product of quality which is related to their and the firm’s
survival. Yet, at the same time, Participants from different
domains work in a system; they have different focuses,
experiences and cultural backgrounds which can lead to
limited understanding of each other. For example,
Engineering professionals use scientific methods to solve
technical problems [25], while industrial designers focus on
social and cultural values of the product, making it difficult
for engineering designers to perceive solutions accurately
[30]. Negotiation and trade-offs are required to bring
participants’ efforts into coherence. So while members of a
collective share a common goal at some level, at another
level their interests will conflict and they strive in
competition. These complex relationships among
participants affect the design ideas transformation process.
Division of Labor : each designer takes in charge of
transforming design ideas into concepts. And other
members in the community help the transformation
between design ideas and concepts by providing useful
information or knowledge.
Rules: rules in sketching system mainly include technical
roles or laws, like accessibility laws; formal and informal
social roles like trust, mutual respect, shared vision,
frequent communication, and flexibility.
Structure of sketching activity: According activity theory,
an activity is oriented by a motive, the actions are oriented
to goals, and the operations oriented to conditions. Only
after an analysis of the current conditions, operations are
executed. Also, sketching activity is a reflection-in-action
process, designers work in a continuously changing
situation. Thus, operations in sketching activity are not
fixed. Figure 11 about the structure of sketching is not
exactly right. It just summarizes some possible operations
when designers are sketching.
Sketching Activity System Development:
Along with the development of sketching system, the
components of this system are dynamic and not static. For
the same designer, Figure 16 shows that sketches which are
generated at the first design stage are the tool of the second
design stage sketching system and concepts in them are the
object.
Figure 16. Sketching activity system development
Tensions between Activity System Elements:
The first tension arises out of collaboration between
designers and other participants in the community who
come from distinct disciplines such as engineering,
business, and sociology. Their different domain knowledge
and value allow them to see the same object from different
perspective. This paper focuses the tension between
designers and engineers, who often collaborate in the
concept design stage. Although they both contribute to new
product’s concept development, industrial designers have a
bias towards appearance and user-interface; whereas
engineers focus on functionality and manufacture to ensure
that the product satisfies the design specification and
manufacturing requirements [15]. Their Working
Approaches are also different. Industrial designers
generally adopt 3D sketches as representations of concepts.
For them, such kind of drawing enhances discussions and
improves spatial and perceptual assessment. But engineers
apply scientific knowledge to ensure that products
optimally meet design specifications with representations in
the form of engineering drawings (see Figure 17) that show
requirements based on quality, performance and cost [11,
8], even when they use free hand drawing to develop
concepts, they love to illustrate the concept in the form of
engineering drawings (see Figure 18). So differences in the
use of tools and methods have made collaboration between
groups difficult [2]. As a participant in a machine tool
design project, I felt this tension between designers and
engineers deeply.

in a design group, novice designers often feel frustrated and
thus affect the collaboration, the quantity and quality of
concepts.
Figure 17. Engineering drawing
The analyses of these two tensions are not exhaustive and
there must be other tensions in sketching activity system.
But these two tensions often appear in design groups and
affect concept development obviously. In other word, the
transformation process between object and outcomes of
sketching activity system is influenced by these two
tensions.
According to all the analysis of sketching behavior above,
for the first one tension, I argue that when a designer
communicates with an engineer, he/she should use both 3D
sketch and engineering drawing to represent his concept, as
shown in figure 19. This combination representing method
not only allows designers to communicate with engineers
conveniently, but can also help designers clarify their
thoughts in order to optimize the final outcome.
Figure 18. Free hand engineering drawing
Tension within Activity System Elements:
The second tension which is caused by difference of design
ability exists in designers, each subject of the sketching
system. Many design study have demonstrated a difference
of design ability among designers in a product design task,
especially between an expert and a novice designer,
because of their different design experience, background,
problem decomposition strategy and so on. One study [29]
has been conducted in an automotive design group,
including six MA automotive design students and six
professional designers who work at the Ford design studio
in Dunton. They were asked to produce a quick concept
sketch; no brief was given as to the type of vehicle design
to be undertaken. They also had freedom of viewing angle,
sketching tools, colours and materials. The results showed
that there were some obvious differences between the two
groups. Professional designers produced many more
sketches in many more views. This demonstrated both a
greater understanding of 3D, and a better using the sketches
to facilitate problem solving and creative effort. Therefore,
Figure 19. 3D sketch and engineering drawing simultaneous to
represent concept
For the second tension, I propose a concept-shared model.
It is illustrated in figure 20. It means after the first design
stage, all designers share the concepts generated in the
previous stage. So if a designer doesn’t have more ideas
about the shapes of the product, other designers’ concepts
can inspire him. This method can improve the quality and
quantity of concepts theoretically, because designers
recognize different shapes when they see the same image.
Figure 21 presents the difference of sketch quantity
between a concept-shared model and concept-independent
model. The concept-independent model, which is used
extensively in the industrial design field, indicates that each
designer only uses his/her concepts through all the concept
design stage.
In summary, combination representing method and
concept-shared model which arise from partially changed
sketching activity can be considered as possible solution to

the question, how sketching can affect concept development
effectively in a design group.
Figure 20. Concept-shared model in concept design process
and recognize a phenomenon, sketching activity, with
which I am familiar.
Although Schön emphasized the importance of ‘reflectionin-action’
in design process, not in all design situation,
designers exhibit a reflection-in-action. Only in the
situation, when designers can work smoothly without
stopping, they are reflecting in action, both on the
phenomena they are representing through their drawing and
on their previous way of thinking about the design problem.
In some design situation, on the other hand, when the
designer pauses to think back over what he/she has done in
a project, exploring the understanding that he/she has
brought to the handling of the task. He/she may, for
example, construct a new theory of the case, reframing the
problematic design situation in such a way as to redefine,
interactively, both means and ends, he/she exhibits a
reflection on action. And I also think that there should be a
reflection-before-action when we plan put before we act
what we want to do.
For activity theory, just like Nardi said “Activity Theory is
a powerful and clarifying descriptive tool rather than a
strongly predictive theory[24]”, Activity Theory provides
us with a powerful theoretical lens to recognize each
component of an activity system and their structure clearly,
especially when we face a more complicated situation. But,
as an analytical tool, it only provides us a general
framework, rather than concrete ways or steps to analyze a
specific activity. Second, it emphasizes contradictions in an
activity system, so it helps us to find out problems in a
system instead of giving solutions to existing problems.
Third, it provides us with a nondualist theory for describing
the inseparability of activity and the environment in which
it happens. From this perspective, context is neither simply
a container nor a situationally created experiential space but
is an entire activity system, integrating the participant, the
object, the tools (and even communities and their rules and
divisions of labor) into a unified whole [10]. Forth, both an
activity system and its components are dynamic and are not
static. But I found few people pay attention to this
characteristic in our discussion.
In summary, these two theories are really helpful for me.
Not only am I exposed to new concepts, but also I start to
consider phenomena from a new perspective.
CONCLUTION
Figure 21. Two design models comparing
The idea of this paper is inspired by two concepts:
“reflection-on-action” and “tension” in an activity system.
“Reflection-on-action”, as the name implies, tells me that a
designer should think about the design process after the
fact. “Tension” makes me to consider the contradiction in
an activity system. Both Schön’s model of design and
Activity Theory give me distinctive perspectives to rethink
As for the study of sketching behavior, it is useful for CAID
(Computer Aided Industrial Design) system design,
especially when the system will support concept
development. The concept-shared model provides an idea
for developing a Collaborative Sketching Technique which
is a hot point of research in CAID.
ACKNOWLEDGMENTS
Thanks to my professor, Ron Wakkary, for providing the
theories and his difficult concepts explanation in the class.

And also thank my classmates who were in the team
discussion.
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