1. 2 Thanks Terry for being the greatest advisor ever and importantly for making me take 6.001....

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Thanks Terry for being the greatest advisor ever and importantly for making me take 6.001. Thanks George for giving me that intersecting rectangle assignment two years back. It sparked this thesis. Thanks Patrick for being such an optimist and taking 6.034 and 6.xxx. A lot of my learning comes from you. Thanks to Takehiko, Axel, Jimmy, Neri, Onur, Sergio, Daniel for patiently enduring my explanations. Your reviews were invaluable.

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From the very early phases of design conception, designers uses sketches as a design tool.

Sketches however are ambiguous. Meanings are associated on fly as the designer ‘comes up’ with certain ideas while working with it.

There is no hierarchy in a sketch. In fact ‘structure’ is established only after meanings are applied to the sketch.

However even in such structurally and conceptually fluid territory, the designer solves most of his design problems and very often comes to quick resolutions.

Sketches are Powerful

Computational Model of Visual Interpretation

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In order to understand the nature of such ‘design exploration’ and augment it with computational support, we must understand the nature of these assertions, how we interact with them and how we visually interpret them.

That is the motivation of this thesis.

Thesis


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- Fluid and Extensible

no apriori declaration of intent

- Ambiguity and Multiplicity of Semantics

parts assume different meanings with interpretation

- Context

realms of thought (site-plan)

- Interpretation

real-world concepts – buildings-courtyard-streets

- Reflection

opportunism in design (emphasize courtyard)

The Sketch Environment


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Current Trends of Design Computation Systems

Current Models: Hierarchical RigidityA sketch has no structural hierarchy. The designer leaps from context to context changing his structural interpretation on the fly. However computation systems have strict hierarchies allowing them to look at the world in a monotonous way.

Also the overheads are so high in developing the structural abstraction that the fluidity of a sketch vanishes and the abstraction itself becomes a design issue.

“Descriptions fix things in computation, and nothing is ever more than its description anticipates explicitly.”[Stiny 1994]

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Current Trends of Design Computation Systems

Current Models: No Reflection

Design process as a SEE – DO – SEE cycle.

Generative systems have no layers of reflection. Hence there is no way the generation can be guided by global principles.

Hierarchical Rigidity

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Stiny


No Structure Computation

WinstonNear-Miss and Learning

MinskySociety of Mind

PapazianPrinciple of Opportunism In Design

UllmanVisual Routines / Spatial Reasoning

PapertKnowledge in Learning

SchonReflection in Design

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Theoretical basis for the Model

Abstraction and Conception SpacesSketches are abstract representations. However, designers use them to explore real world concepts. The actual shapes that form the sketch physically comprises the abstraction space, while concepts that the abstractions trigger in the designers mind make up the conception space.

Shape A

Concept1

Concept2

Concept3

Shape A

Concept1

Concept2

Interpretation 1

Interpretation 2

(Notice the structural / topological difference)

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Shapes and Concepts- Shapes are the real visual assertions, while concepts are imagined.

- Hence concepts might not have physical existence in the geometry. In fact Concepts need not have any geometric descriptions at all.

- Shapes are a flat collection of parts, while concepts have hierarchy. Interpretation gives concepts their hierarchy.

- Concepts have multiple descriptions, strengths, and even actions-rules associated with them.

Shape Concepts

ENCLOSURE

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Schemas are reasoning modules independent of structure and can perform reasoning using geometric, functional, relational or logical predicates.

Schemas – Procedural Knowledge Units


(If ‘assertionIS ‘(gathering-place)IS ‘(next-to-buildings)Then MAKE-COURTYARD-CONCEPT)

Assertions

Schemas

TriggerTrigger

Generate

Concepts

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Schemas – Types


(courtyard) -> (enclosure) -> ‘(unsorted (edge,edge,edge,*))

-> ‘(unsorted (edge,edge,*,*))

(alley) -> (or (and (aspect, (more-than 2)) (sorted (gap, edge,gap,edge))

(and (aspect, (less-than .5) (sorted (edge,gap,gap,edge)))

GEOMETRIC (Description)

RELATIONAL (Constraints)

(courtyard) -> (not (inside (figures)))

(courtyard) -> (not (next-to (courtyard)))

REASONING (Consistency)

(courtyard) -> (not (inside (room)))

FUNCTIONAL (Higher Level Design Concepts)

(courtyard) -> (gathering-place) -> (adjacent-to (many (building))) (courtyard) -> (has-a fountain)

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Schemas are learnt from real world interaction and experience. They are used to schematically store our knowledge about the world.

Schemas – Learning


Schemas can trigger other schemas within the context as well. For example, a courtyard-schema might trigger entrances-schema or fountain-schema. Therefore, Schemas also gives a structure to the entire conception space as well.

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Active + Passive = Imagined World


The ‘Imagined world’ which contain many ways to look at the world. The shape in the figure is neither resolved as a collection of three line concept nor as a single planar concept, but all the concepts are simultaneously present.

Subsequent selection of sub-sets of active agents creates a partial-mental state and allows us to imagine the assertion as either three lines or a planar concept.

Active Assertions

Passive

Assertions

Passive

Assertions

Passive

Assertions

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PASSIVE

ACTIVE

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FocusIn this framework, the perceptual focus manager selects a subset of the shape assertions in the ‘world’.

To simulate gaze in a simple manner the lisp LISP machine creates a boundary of preset dimensions, randomly places it in the sketchpad and selects the visual assertions, which are completely or partially inside the imposed boundary

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Computational Model of Visual Interpretation Computational Model of Visual Interpretation

Passive Assertions

Direction-ideas Figure-ideas

Position-ideas Edge-ideas

Multi-representation creates are strong knowledge-base.

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Schema generates the conceptThe courtyard concepts are generated by the following schema,

(courtyard-schema) ->

(concept which-is-in ‘world

which-is-not-inside ‘figures

which-is-not ‘too-wide ‘too-long

which-has ‘(edge edge edge edge)

which-has ‘(edge edge edge)

which-is-not ‘too-small )

These concepts are added to the ‘Imagined World’, for the next cycle of interpretation. By default, the concepts remain as ‘passive’ assertions.

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Action-Rules Action-rules embedded in the courtyard-concepts can be used to add ‘active assertions’ to the abstraction space.

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Example Runs

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TRIGGER as an exploration toolIt makes explicit a large set of possibilities, without any bias. There can surprising opportunities that the human designer might have missed.

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Sketches with Performance Criteria

Evaluation modules can directly process the sketches and suggest high-performance alternatives.

TED I FOUND A NARROW ALLEY…

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Shape Grammar ImplementationExact structural match would not be necessary for triggering rules.

This rule can match the assertions below

1. 2 Thanks Terry for being the greatest advisor ever and importantly for making me take 6.001....

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