BPC: Art and Computation – Summer 2007BPC: Art and Computation – Summer 2007

DAFFIE Technical PresentationDAFFIE Technical Presentation

Erik Brisson

ebrisson@bu.edu

BPC: Art and Computation – Summer 2007 2

OutlineOutline

BPC: Art and Computation – Summer 2007 3

What's in a virtual world?What's in a virtual world?

BPC: Art and Computation – Summer 2007 4

What's in a virtual world?What's in a virtual world?

An environment Representations of physical objects

– Visual models– Auditory elements

Interactions with objects Representations of people - avatars Communication

– Gesturing– Telephony– Video

BPC: Art and Computation – Summer 2007 5

Our goals with DAFFIEOur goals with DAFFIE

Distributed

Interactive

Visually and aurally rich

Input (models, images and sounds) from variety of available tools

Simple import method

Script driven

Accessible to non-expert users

Extensible by programmers

BPC: Art and Computation – Summer 2007 6

Traditional animationTraditional animation

SequenceSequence of framesof frames Hand drawn or “captured”Hand drawn or “captured”

BPC: Art and Computation – Summer 2007 7

Animation example - 3D modelsAnimation example - 3D models

Model sequence What is changing?

– Shape

– Elements• movement

• Rotation

• Scale

– Whole object• Movement

• Rotations

• Scale

BPC: Art and Computation – Summer 2007 8

Design decision - animation by Design decision - animation by model sequencesmodel sequences Allows importation of work from many sources Allows reasonable method of animation Allows input from many tools

– Allows artists to create using their favorite software

– E.g., Maya, Lightwave3D Gives simple import methodology

– Uses Performer loader Avoids import of behavior (avoids programming)

BPC: Art and Computation – Summer 2007 9

Animation - arp scriptsAnimation - arp scripts

Allows control without programming– Developed quickly, early on for class project– Simple, has been used many times

Control– Position– Rotation– Scale

Timing of playback

BPC: Art and Computation – Summer 2007 10

arp script example: basic arp script example: basic sequencesequencearp 2.0

name clusterseq

geom_path ./

playspeed 10

frame

geom_show clustergeom0000.obj

frame

geom_show clustergeom0001.obj

frame

geom_show clustergeom0002.obj

frame

geom_show clustergeom0003.obj

end

BPC: Art and Computation – Summer 2007 11

The DAFFIE scene graphThe DAFFIE scene graph

The world-room-group-sequence hierarchy

World

Room Room

Group GroupGroup Group

Sequence Sequence Sequence

Sequence

Sequence Sequence

BPC: Art and Computation – Summer 2007 12

3D Coordinate system3D Coordinate system

BPC: Art and Computation – Summer 2007 13

arp scripts: arproom filearp scripts: arproom file

arproom 2.0

name cart-modelsenter_xyz 3.0 4.0 4.0enter_hpr 30.0 -98.0 0.0

group_xyz 0 0 0group_hpr 0 0 0group_path ../models/purple_cube/group purple_cube.arpg

group_xyz 2 -4 0group_hpr 60 0 0group_path ../models/blue_cube/group blue_cube.arpg

group_xyz -3 -5 2group_hpr 0 0 0group_path ../models/orange_sphere/group orange_sphere.arpg

end

BPC: Art and Computation – Summer 2007 14

arp script: arpgroup filearp script: arpgroup file

arpg 2.0

name gbdog

geom_size 1.0geom_path ./geom_hpr 0 90 0geom_xyz 0.0 0.1 0.0geom_rep dog0.objtrigger_method cycleseq_path ./seq_hpr 0 90 0seq_xyz 0.0 0.1 0.0seq_file gbdog.seq

end

BPC: Art and Computation – Summer 2007 15

arp script example: basic arp script example: basic sequencesequencearp 2.0

name clusterseq

geom_path ./

playspeed 10

frame

geom_show clustergeom0000.obj

frame

geom_show clustergeom0001.obj

frame

geom_show clustergeom0002.obj

frame

geom_show clustergeom0003.obj

end

BPC: Art and Computation – Summer 2007 16

darp script example: move objectdarp script example: move object

frame

geom_show pot21.iv

geom_xyz 5.0 2.1 9.3

geom_hpr 0.0 90.0 0.0

geom_show drop21.obj

frame

geom_show pot22.iv

geom_xyz 5.5 1.9 3.2

geom_hpr 0.0 91.0 0.0

geom_show drop22.obj

BPC: Art and Computation – Summer 2007 17

arp example: change object sizearp example: change object sizearp 2.0name benThorn_seqgeom_path ./playspeed 4sound_path ../configs/frame geom_scale 0.56 0.56 0.56 geom_show btw1.objframe geom_scale 0.42 0.42 0.42 geom_show btw1.objframe geom_scale 0.56 0.56 0.56 geom_show btw1.objframe geom_scale 0.7 0.7 0.7 geom_show btw1.obj

BPC: Art and Computation – Summer 2007 18

Design decision - sound clipsDesign decision - sound clips

SimplicityGives simple import methodologyAllows input from many toolsUses commonly available format

(.aiff)

BPC: Art and Computation – Summer 2007 19

Example - adding soundExample - adding sound

frame geom_show clustergeom0000.obj sound_xyz_stereo 180.932040 -157.771123 -103.679324 180.932040 -43.291371 -103.679324 sound_move h2o4.aif sound_trigger h2o4.aifframe geom_show clustergeom0001.obj sound_xyz_stereo 187.016266 -157.446847 -103.679324 174.847813 -43.615647 -103.679324 sound_move h2o4.aifframe geom_show clustergeom0002.obj sound_xyz_stereo 193.031556 -156.477695 -103.679324 168.832524 -44.584799 -103.679324 sound_move h2o4.aif

BPC: Art and Computation – Summer 2007 20

The view frustumThe view frustum

What you actually seeUnits matter (DAFFIE uses feet)

BPC: Art and Computation – Summer 2007 21

Navigation - user experienceNavigation - user experience

The 6 degrees of freedomThe 6 degrees of freedomHow map onto various input devicesCommunication with viewer (old

model)– direct sending of xyz,hpr wand motion

to viewer

BPC: Art and Computation – Summer 2007 22

The DAFFIE event systemThe DAFFIE event system

Communication between agents

Navigator Viewer

Navigator

Viewer

Sound server

Event Server

App agent

App agent

App agent

Telephony Video agent

Sound server

BPC: Art and Computation – Summer 2007 23

Triggering objectsTriggering objects

Light stick (by viewer)Proximity (by viewer)Proximity (by agent)Other (by agent)The trigger event

BPC: Art and Computation – Summer 2007 24

World state and eventsWorld state and events

Object descriptionsTriggerTransformsSwitchesNavigationSoundVideoEtc.

BPC: Art and Computation – Summer 2007 25

Agents and eventsAgents and events

Using events to control elements of the world– Triggering sequences– Moving objects– Changing rooms– Navigation

BPC: Art and Computation – Summer 2007 26

Navigation by agent sending Navigation by agent sending eventseventsNew model - sending of transform

matrices to viewerKeeping track of avatars

BPC: Art and Computation – Summer 2007 27

TelephonyTelephony

Telephony collector agent– Gets audio stream from microphone– Chops into sound samples– Sends sequence of sound samples

Sound server– Receives sequence of sound samples– Reassembles audio stream from sound

samples– Sends reconstructed audio stream to speakers

BPC: Art and Computation – Summer 2007 28

Video texture mapsVideo texture maps

Video as sequence of imagesVideo generator

– Sends sequence of imagesViewer

– Receives sequence of images– Uses texture mapping on an object in

scene

BPC: Art and Computation – Summer 2007 29

Stereo displaysStereo displays

Physical issues and camera issues– Using polarizing filters– Setting up the view– What looks closer vs further– Relative position to the screen and

viewer

BPC: Art and Computation – Summer 2007 30

Tiled wallsTiled walls

Issues and differences– Head node vs render nodes– Event management / avatars / triggering– Virtual cameras– Alignment

BPC: Art and Computation – Summer 2007 31

The EndThe End