PHIDIAS: Integrating CAD Graphics into Dynamic Hypertext

Raymond J. McCall , Patrick R. Bennett , Peter S. D'Oronzio , Jonathan L. Oswald , Frank M. Shipman, III , Nathan F. Wallace, PHIDIAS: integrating CAD graphics into dynamic hypertext, Hypertext: concepts, systems and applications, Cambridge University Press, New York,

NY, 1992

Background PHIDIAS is a hypermedia based computer aided design system (HyperCad)

Developed due to the need of environmental design Intended to assist environmental designers

• Landscape, architecture, interior designers Provides support for two processes

• Construction of form• Argumentation of construction

This is accomplished through the use of CAD graphics and IBIS argumentation

IBIS background Issue Based Information System

Organizes design discussion around the deliberation of issues

Issues are design questions, deliberation is the process of arguing the pros and cons of proposed answers to the questions.

Components making up IBIS• Issue• Answer (position)• Argument• Resolution

Issues are resolved by selecting answers on the basis or the argumentation

Background Through not developed to explore hypermedia technology the PHIDIAS project addresses several timely hypermedia questions Search and query in hypermedia network Virtual structures Computation in(over) hypermedia networks Composite nodes New approach to large collections of vector data• Through the replacement of “layers” concept with the concept of graphical clusters

PHI approach to IBIS Procedural Hierarchy of Issues (PHI) extends IBIS, widening the scope of the concept issue and altering the inter-issue structure. In PHI every design question is an issue,

• even if it hasn’t been deliberated Uses relationships indicating discrepancies between issues

Serve relationship indicates the resolution of one issues that influences the resolution of another issue

Design is represented as a tree like structure of nested issue resolution processes

Each project has a single root issue defining the project

Computer Support for PHI User controlled journeys through a network is the central goal of MIKROPLIS, the core of PHDIAS MIKROPLIS is a hypertext system

• Nodes are of arbitrary length• Includes a navigation and query language

• That allows both content and structure searching• Integrates authoring and browsing, editing and restructuring

• Outline oriented idea for a PHI tree like structure

• Can handle any graph with labeled links• Lack of vector graphics prevented its use in environmental design

Computer Support for PHI Original plan was to allow vector graphics to

interlace with PHI texts, but this proved insufficient It was found the design student has problems thinking in terms of issues, answers and arguments while they were devising form (drawing)

Think allowed protocols showed though their thinking could be mapped onto PHI structure• Why did they say they couldn’t think the way they were thinking?

Due to the continual alteration between action and reflection “Reflection-in-Action”• To construct form the design needs to work unselfconsciously while engaged

• Attempting to reflect about this while in action halts the process.

Computer Support for PHI “Reflection-in-Action” takes place when action breaks down:

Designer’s action results in unanticipated consequences (good or bad)

The designer is stuck and doesn’t know what action to take next

Thus design is broken into Construction

• shaping the form of the solution (with CAD) Argumentation

• the kind of reflection dealt with in PHI • The task then becomes making argumentation part of reflection

To support this RIA, the issue relevant to a construction task must be brought to the designers attention while that task is still at hand, but not interfere with construction

The PHIDIAS System PHIDIAS provides integrated authoring and browsing, an applicative query language and dynamic restructuring of the issue base using virtual structures. Designers need to be able to modify the issue base as they navigate through it, for their understanding and views and problems• For this authoring must be highly integrated with browsing, which PHIDIAS supports

To enter issues, answers or arguments while browsing the user points to text or the graphical node and indicates the link(s) to be used.• To edit an existing node the user points to that node and selects edit

PHIDIAS Screen Layout

The PHIDIAS Query Language In PHIDIAS the hyper-document is always displayed as a result of some statement in PHIQL Analogous to a data base “view” Allows nodes to be clustered in user-specified configurations

PHIQL allows both structure and content based retrieval, separately or in combination Is English like, so users can gain understanding

Link types are the primitive operators

Virtual structures To allow for this auto restructuring, PHIDIAS uses

virtual structures i.e. queries embedded at nodes

• When asked to display a node the query is evaluated and result is displayed

• This makes display conditional on acceptance of the answers they presuppose

This auto updates changing information• The structure of the hyper-document appears to change as a function of user input

Reduces the size of the hyper-document through the elimination of irrelevant substructures, facilitating use of large argumentative networks• May be combined with “application”, “composition” “construction” with operators to create queries

Virtual structures When users edit the issue base, there are implications for altering other parts of the issue base

Example If a user rejects answer 1 on issue 102 should not have to deal with issue 104

It should disappear from the issue base

Un-pruned Pruned

Support for construction Support is through domain specific construction kits, holding the building blocks for a type of design object i.e. bathroom Each block is a node in the hyper-document

Blocks are assembled into objects which in turn become nodes

Assembly is done through a direct manipulation graphics editor

Integrating construction and argumentation The system must know what construction task the designer is involved in to provide access to the precise section of the hyper-document relevant to the task. Otherwise this information is virtually worthless because it won’t get used.

PHIDIAS does this through button clicks triggering during construction to execute canned PHIQL queries i.e. when a fridge is chosen it will prompt certain information about the fridge and give argumentation about placement

Conclusion Future work Virtual structures are powerful resources that could be used for intelligent restructuring of hypermedia networks They provide a venue for computation over the network, virtual network structures that call other virtual structures be creating the possibility of recursive computation.

If queries are able to test conjunctions and disjunctions of conditions virtual structures can be used for basic logical programming• Allowing PHIDIAS to make complex inferences based on user input

Conclusion A requirement for good design is “reflection-in-action”

Systems should support integration for both construction of solution form and argumentation regarding that construction Hyper-media is a natural venue for creating this kind of design environment• To do this PHIDIAS utilizes:

• Applicative query language• Searching both content and structure

• Virtual Structures• Composite graphic nodes• Query-based graphic clustering• Triggered queries

Questions Starting and stopping the creative flow is a

continuing issue for many using computers in design or problem solving What systems or tools do this well? What systems do this poorly?

We have seen other hypertext systems try to aid design, creativity and activities associated with this (sketching, drawing, modeling) Why do you think they continue to fall short? What technology advance needed to fully integrate it? Or will this ever be done?

What current systems do you think support highly integrated browsing and authoring? Why are they successful?