Copyright (c) by Rajarathinam A. & Gadh R, 2000 Geometric Modeling in Multi-modal Multi-sensory...

Copyright (c) by Rajarathinam A. & Gadh R, 2000

Geometric Modeling in Multi-modal Multi-sensory Virtual Environment

Arangarasan Rajarathinam

[email protected]

http://www.cs.wisc.edu/~arangara/

Ph.D. Student, UW-Madison

Other Team Members

Dr. Tushar H. Dani

Mr. Chi Cheng Chu

Mr. Xiaochun Liu

Prof. Rajit GadhDirector, I-CARVE Lab

Professor in ME Department

University of Wisconsin-Madison


Introduction

• Conventional CAD systems and limitations• How VR enables to overcome these limitations?• COnceptual VIRtual Design System (COVIRDS)• Detailed Virtual Design System (DVDS)• Intelligent Assembly Feature (Smart-Mates)• Hardware setup (Virtual Design Studio - VDS)• Summary & Future research


Conventional CAD Systems

• Not suitable for concept shape modeling

• Bottleneck in I/O Interface

• Mapping Process in I/O Interface

• Single User System

• Collaboration becomes difficult

Human sensories used: Hand, fingers, and eyes.

1D-Space

2D-Space

3D-Space

1D 2D

2D 3D

2D 3D

Keyboard

Fingers

I/O Devices Mapping Modeling space

Monitor

Eyes

Mouse

Hand, Fingers

Human sensories used: Hand, fingers, and eyes.

1D-Space

2D-Space

3D-Space

1D 2D

2D 3D

2D 3D

Keyboard

Fingers

I/O Devices Mapping Modeling space

Monitor

Eyes

Mouse

Hand, Fingers


Motivation

• Develop concept & detailed virtual design system– High through-put of I/O interface

– Intuitive & rapid modeling process

– Visualization & manipulation of complex models

– Collaborative design by multiple designers


Multi-modal, multi-sensory VR interface

Voice

Stereoscopic Display

Mouth (Speech)

Hands, head, body(3D Position Tracking)

Eyes (Visual)

3D – Motion

Gesture

Fingers (Haptic)

Force Feedback

Skin (Tactile)

Synthesised 3D-Sound

Ears (Auditory)

I/O DevicesModeling space

1D-space

2D-space

3D-space

• Human Sensories used: Mouth, fingers, hands, head, body, eyes, skin and ears.

• Eliminates mapping process.

• Direct manipulation of models.


Speech Interface

• Geometry Editing– Create– Delete– Modify/Dimension

• Geometry Manipulation– Selection– Location– Query

• Navigation– Zoom in/out– Viewpoint orientation


Hand Gestures and Actions

PointingReleaseGrasp

Translation

Rotation

Ring Okay

Resize ViewpointTransformation


Additional Interaction Methods

• Input Interface– 3D Menu

– 3D Toolbars

– Sliders

• Output Interface– Synthesized voice

– Text output


COVIRDSCOnceptual VIRtual Design System

• Architecture• Geometric modeler & representation• Free-Form Surface Modeler• Examples• Limitations


COVIRDS - Architecture Designer

ACIS

Workspace Instances Speech Locator (WISL)

Navigation

Selection

Manipulation

Interaction

Design Rules

Snapping & Location

Shape Elements & ‘Add’ Operation

Modeling

Design Editing Tools

WTK Scene Graph(Device drivers, collision detection etc.)

Design Intent Graph (D)Constraints, Grids, Design rules etc.

Shape Modeling Graph (S)Rapid editing, Constraint enforcement, Rule evaluation

Virtual Modeler

Graphics/Geometry API

User Interface

Graphics/Geometry/CAD

Solid Modeling Kernel

User


• Design Intent Graph, D– Captures designer’s intent

– Depends on Sequence or operations

• Shape Modeling Graph, S– Geometric representation of part

– Additional attributes to enable high-speed editing

Intermediate Geometry Representation

block b1

rib r4 boss o2boss o3

b1

r4o2

o3

D

+ +

+

b1

r4o2

o3

S

A A

A


Parametric Surface Model


Assembly Models


Limitations

• Has its own geometric representation• Data translation between CAD systems• Not efficient for detailed shape modeling


DVDSDetailed Virtual Design System

• Architecture• Functional difference between CAD Systems &

DVDS• Sketching• “Liquid Features”• Parametric Features• Data Translation• Examples


DVDS - ArchitectureDVDS

CAD System

-

Data-base

-

(e.g.)

DE

SIG

NE

R(s

)

Com

man

d

Par

ser

En

gin

e

Voice Recognition

Spatial Recognition

Gesture Recognition

Gra

ph

ics

En

gin

e

Stereoscopic Display

Auditory Feedback

Designer(s) Space

Hardware Layer

DVDS

CAD Application


Sequence of Operations

Bi-directional operations

Uni-directional operations

Geometric Space

User Interaction Space

Draw Sketches

Add Feature Definition

Add Feature Options

Define Sketchplane

Update PART Model

Create Feature

Conventional CAD Systems


Update PART Model

Define Sketches

Add Feature Options

Create Feature

In DVDS

Draw Sketches


Add Feature Options

Define Sketchplane

Update Part Model

Create Feature

In Conventional CAD Systems


Sketching


“Liquid Features”


Sketched Features


Direct Features


Parametric Feature Definitions


Library Features


Data Translation

- Editable - Full feature definition - Restores history

Native Geometry (of CAD system)

Imported Model

Imported Model

- Editable - No past features - No history

- Non editable (Display only) - Triangulated

Properties

- Solidworks “PRT”

Types E.g.

- Parasolid - SAT - VDAFS - STEP - IGES

- VRML - STL - PROE Render


Example Models


Smart-Mates

• B-Rep models.• Cost function.

– E.G. Planar faces.• Function of angle, projected

area, shortest distance, area, etc.

– E.G. Conic faces.• Function of angle, radius, etc.

• Minimize cost function.• Optimization for rapid

computation.– At-least 60 fps in stereo mode.

R

F1

F1’

F2

F2’

D


Smart-Mates for B-Rep Models

B-Rep models

Features extraction

FeatureN(higher order)

Feature1(e.g. Planar faces)

Feature2(e.g. conic faces)

Cost Function1 Cost Function2 Cost FunctionN

Choose the best pair

Pre-Computed

Compute during the simulation


Potential Face Pairs

• Definition of cost function plays a vital role.• Cost function varies based on the kind of geometries,

applications, standards, rules, etc.• For a selected face in one part, the potential face pairs in

the other model is shown in the above figure.

Model - A Model - B

Selected Face

Highlighted Faces


Different Face Pairs at Different Orientation


Feature Comparisons Features

Con

vent

iona

l C

AD

Sys

tem

s

C

OV

IRD

S

D

VD

S

Concept design No Yes Yes Detailed design Yes No Yes Parametric modeling Yes Limited1 Yes Intuitive design steps No Yes Yes Industry standard CAD representation Yes Limited2 Yes3 Multi-modal input No Yes Yes Multi-sensory interface No Yes Yes Immersive display No4 Yes Yes Collaborative design No No4 Yes

1 – Primitive based parametric modeling 2 – Maintains its own representation and file format 3 – Uses the same representation as that of the underlying CAD system 4 – Allows only for viewing, not in editing mode


Virtual Design Studio (VDS)

For COVIRDSFor DVDS


Collaborative Virtual Environment


Summary

• VR Technology for Geometric Modeling

• COVIRDS – Concept Shape Modeling System

• DVDS – Detailed Geometric Modeling System

• Smart-Mates – Feature for intelligent assembly

Benefits• Rapid & Intuitive Design Process

• Eliminates the need for expensive physical prototyping

• Reduces product cycle time and thus Cost effective

• Enables “human in the loop” analysis


Future Research

• Collaborative Virtual Environment• VR2VR – Advanced Collaborative Visualization• VR – Integration with human modeling software

e.g. Jack, Safework


Acknowledgment

• Government– NSF, DOE, EPA, NASA (Federal)

– UIR, Solid Waste Program, WARF (State)

• Industrial Partners– Ford, Pratt & Whitney, Caterpillar, Lucent, AT&T,

Texas Instruments, FIAT, CMI

• New Alliances– General Dynamics, Boeing, Chrysler

Copyright (c) by Rajarathinam A. & Gadh R, 2000 Geometric Modeling in Multi-modal Multi-sensory...

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