Rapporteur's Summary:
VR99:
Session 2.
Sketches, and Icons, and Features,
Oh My!
Rapporteur's Summary: Session 2
Initial Comments
``Somewhere over the rainbow, way up high,
There's a land that I've heard of, once in a lullaby,
Somewhere over the rainbow, skies are blue,
And the dreams that you dare to dream really do come true.''
Many aspects of visual and spatial reasoning in design are
just starting to be investigated, and much is still at the ``dare to
dream'' stage of development.
Session 2 included dreams by
Forbus,
Park &
Gero,
Leclerq,
Li and
McFadzean &
Cross. Their
papers covered the topics of qualitative spatial
reasoning, a representation for qualitative reasoning about similarity
of shape, a tool for interpreting conceptual architectural sketches,
properties of shape schema grammars, and the relationship between
design events and graphical events while sketching.
Themes
The discussion following the presentation of papers centered mostly
around the role of sketching, sketching conventions, icons, and the
definition, detection and use of features in spatial reasoning. In
the brief summary of the main points of the discussion given below,
bullets are used to provide the main points, with text annotations as
needed. While the bullets were issues raised during the discussion,
the points made in the annotations may not have been.
Sketches:
- What are the roles of a sketch? of sketching?
How to interpret a sketch depending on role?
{ It's clear that sketches can be used as a memory aid, to
evaluate a proposed solution, to deliberately attempt to trigger
associations with known previous designs or known problem
decompositions, to refine requirements, etc. What other roles
are there? Can one interpret a sketch without
previously knowing its role? }
- Is there a competence/performance issue wrt sketching?
{ Is there an underlying language of sketching? Can personal
variations in sketching, and sketching errors be filtered out
to determine the underlying meaning?
- If marks form "words" does personal sketching skill form a dialect?
{ Do different sketchers use different marks? Do different sketchers
have different but consistently used mark vocabularies?
- How can we take advantage of sketching conventions?
{ Can conventional sketching `marks' act as islands of certainty
when trying to understand a sketch?
- How can we avoid making interpretations too early when representing sketches?
{ Representations of sketches in the computer need to be composed
from primitives. These primitives need to have meaning if the
representation is to be useful. The mere act of representing a
sketch makes a commitment to a particular interpretation of the
marks. More interpretation leads to a smaller representation and
more direct use of the representation. However, once the sketch
is represented in a certain way -- i.e., once a particular
interpretation is imposed -- it is hard to interpret it in
another way. }
- How does sketching structure relate to the structure of design reasoning?
{ Can the reasoning being carried out during designing be
detected by looking at the sketching process? at the sketch
produced? For example, do the breaks in the sketching process
correspond to consideration of design alternatives, or does it
indicate design decomposition? Does the precision of the marks
indicate the stage of the design process? (e.g., conceptual) }
- How do sketches affect thinking?
How does sketching affect thinking?
- What is the role of the tool?
e.g., how much is it suited to `providing ambiguity'?
{ Sketching can both help and hinder designing. For example,
if the sketching tool isn't capable of producing the kind of
ambiguous and suggestive marks that the user wishes to make,
then this impedes natural and successful communication. }
- What is the role of the user's skill?
- i.e., with the tool.
- i.e., with the use of sketching conventions.
{ The tool may have all the capabilities required,
but the user may be unaware of them, or may not be
skilled in their use, leading to stilted communication. }
- What is the role/status of sketch?
Is precision required? Is it a `throw-away' sketch?
{ Sketching places demands on the user to supply information
that can then be recorded in the sketch. If the sketch is
intended to be a precise record of a detailed portion of the
design then the user is required to include all the
details. Thus sketching may in places `drive' the detailed
design process. }
- How do expert and novice sketchers differ?
{ Do they sketch differently? Can the user's status as
an expert or a novice be easily determined from the sketch?
Does the act of sketching affect their design thinking in
different ways? Do they reason using sketches in different
ways? Do they tend to assign different roles to sketches? }
Features:
- What are the features?
i.e., what regularities are worth noting for use?
e.g.,- patterns of pen pressure over time;
- indentations in line sequences;
- "shared space";
- holes punched in the paper with the pen; etc.
{ Depending on one's point of view, there are many possible things that
might be considered a feature. If the goal is to try to detect user
frustration, or a poor quality of support surface under the pen,
holes punched into the paper (instead of marks) might be
appropriate features. }
- As features represent points of view, and have reasoning utility:
- what are the appropriate points of view?
- what are the corresponding "sketch features"?
{ What points of view are there? Why do we need the features?
What features will allow us to reason about a user's goal,
level of expertise, design reasoning, or emotional state? }
- Features in drawings and sketches:
- what to look for (i.e., level of detail)
- effect of `purpose' of extraction?
{ Features exist at many different levels of detail, and in many
different `dimensions'. For example, in time, one might be
interested in a pause, in a change of speed during the drawing of
a line, or the number of marks per minute. What can different
dimensions tell us? What can different levels of detail tell us? }
Icons:
- Continuum of "iconness"
- abstraction, mapping, ...
- geometry, topology, color, texture, ...
- whether drawn to scale or not
{ Icons are intended act as a reminder of the thing they
represent, so they have to have the power to remind us of the
original. Icons are often abstracted graphical representations
of the original. As abstraction is a process, and there are
usually many ways to abstract something, and many possible
degrees of abstraction, this suggests that there is a continuum
of "iconness". How then can one determine whether a graphical
entity is an icon or not? }
Version:
Wed Aug 11 21:46:21 EDT 1999
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