copyright (c) by rajarathinam a. 2000 geometric modeling and collaborative design in a multi-modal...

Copyright (c) by Rajarathinam A. 2000

Geometric Modeling and Collaborative Design in a Multi-modal Multi-sensory

Virtual EnvironmentRajarathinam Arangarasan

Ph.D. Student, UW-Madison


Introduction

• Conventional CAD systems and limitations• How VR enables to overcome these limitations?• Detailed Virtual Design System (DVDS)• Intelligent Assembly Feature (Smart-Mates)• Hardware setup (DVDS)• Collaborative Virtual Environment (V2V)• Summary & Future research


Conventional CAD Systems

• Not suitable for concept shape modeling

• Bottleneck in I/O Interface

• Mapping Process in I/O Interface

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



• Single User System

• Collaboration becomes difficult


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

• 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


Parametric Surface Model


DVDSDetailed Virtual Design System

• Architecture• Functional difference between conventional 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


Add Feature Definition

Update PART Model

Define Sketches

Add Feature Options

Create Feature

DVDS


Sketch Entities

Control Points Moving handle

Rectangle

Sketch Primitives

Control points

Description

Two extreme points

Circle Center and radius

Circle 3 points on circumference

Ellipse Center, point along major and minor axis resply.

Arc Center, starting point and ending point on arc

Arc Start, End and another point on arc

Polyline End points of each line segment

Spline Spline along the control points

Centerline End points of line segment


Sketching


Liquid 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


Detailed Virtual Design System

For DVDS


Designer in DVDS


Multiple designers in aVirtual Environment


Collaborative Virtual Environment (V2V)

• Architecture• Data types and management• Network topology and Session management• Interface Modalities• Clients Connectivity & Interface Modalities


V2V - Architecture

Server - 1

C-1 C-2 C-n

Server - 2 Server - n

CODES ManagerO1, O2

O3

O1


Data types and Management

DataType

Amount of data transmission Required network

bandwidth

Example

applicationAt session starting

During simulation

DD Varies from SSHS

Varies from SSHS

> 100Mbps Simulation of CFD analysis

PD Varies from SSHS

Varies from SSMS

10Mbps ~ 100 Mbps

Geometric modeling

SD

Varies from SSHS

SS 24 Kbps ~ 10 Mbps

Visualizing static objects

IC Varies from SSMS

SS 24 Kbps ~ 10 Mbps

Interaction between clients

DD - Highly Dynamic Data IC - Interface CommunicationsPD - Partially Dynamic Data HS - Huge sized data setsSD - Static Data MS - Medium sized data setsIC - Interface Communications SS - Small sized data sets


Server, Client and CODES manager

Server

Cache Objects

Shared Methods

Shared Objects CIM Table

ASO Table

Server side communication

library

Local cache of shared objects

CIM table

Client side communication

library

Client

Applications library

Interface modalities

library

CODES manager

Client side communicatio

n libraryCached Objects

CIM Table

ASO Table Server side

communication library


Interface Modalities

Voice input

Video

Glove Data

3D Position / Orientation

Convert to text + emotional info.

Streamed

Streamed

Series of images of both the eyes

Viewpoint Information

Gesture ID

3D TrackingPerform the

appropriate action

Combine text and emotional info.

Use both images for stereo display

Render the scene for this viewpoint

Visual display

Play

Display

N E T W O R K

Sender’s perspective Receiver’s perspective


Clients Connectivity and Interface Modalities (CIM) Table

CS – Centralized data V – Voice input S – Stereoscopic displayRP – Replicated data G – Gesture M – Monocular displayT – 3D tracking A – Audio output

Client System

Type of Connection with server

References Available I/O Interface

Modalities

Policy

From To

C1 CS C2, C4 C2, C3 V, G, T, S, A A-

C2 CS C1 C1 V, T, M M-

C3 RP C1 G, T, S, A

C4 CS C1 V, G, T, S


Summary

• VR Technology for Geometric Modeling• DVDS – Detailed Geometric Modeling System• Smart-Mates – Intelligent assembling• V2V – Collaborative Virtual Environment

Benefits• Rapid & Intuitive Design Process• Eliminates the need for expensive physical

prototyping• Reduces product cycle time and thus Cost effective


Future Research

• V2V - Advanced Collaborative Visualization• Integration with digital human modeling

copyright (c) by rajarathinam a. 2000 geometric modeling and collaborative design in a multi-modal...

Documents

difficultcopyright c

handlerectanglecopyright

sketchingcopyright c

direct featurescopyright

io interfacecopyright

library featurescopyright

liquid featurescopyright

multiple designerscopyright