1. BPC: Art and Computation – Summer 2007 DAFFIE Technical Presentation Erik Brisson ebrisson@bu.edu

2. BPC: Art and Computation – Summer 20072 Outline

3. 3 What's in a virtual world?

4. BPC: Art and Computation – Summer 20074 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

5. BPC: Art and Computation – Summer 20075 Our 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

6. BPC: Art and Computation – Summer 20076 Traditional animation Sequence of frames Hand drawn or “captured” Hand drawn or “captured”

7. BPC: Art and Computation – Summer 20077 Animation example - 3D models Model sequence What is changing? –Shape –Elements movement Rotation Scale –Whole object Movement Rotations Scale

8. BPC: Art and Computation – Summer 20078 Design decision - animation by model 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)

9. BPC: Art and Computation – Summer 20079 Animation - 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

10. BPC: Art and Computation – Summer 200710 arp script example: basic sequence arp 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

11. BPC: Art and Computation – Summer 200711 The DAFFIE scene graph The world-room-group-sequence hierarchy

12. BPC: Art and Computation – Summer 200712 3D Coordinate system

13. BPC: Art and Computation – Summer 200713 arp scripts: arproom file arproom 2.0 name cart-models enter_xyz 3.0 4.0 4.0 enter_hpr 30.0 -98.0 0.0 group_xyz 0 0 0 group_hpr 0 0 0 group_path../models/purple_cube/ group purple_cube.arpg group_xyz 2 -4 0 group_hpr 60 0 0 group_path../models/blue_cube/ group blue_cube.arpg group_xyz -3 -5 2 group_hpr 0 0 0 group_path../models/orange_sphere/ group orange_sphere.arpg end

14. BPC: Art and Computation – Summer 200714 arp script: arpgroup file arpg 2.0 name gbdog geom_size 1.0 geom_path./ geom_hpr 0 90 0 geom_xyz 0.0 0.1 0.0 geom_rep dog0.obj trigger_method cycle seq_path./ seq_hpr 0 90 0 seq_xyz 0.0 0.1 0.0 seq_file gbdog.seq end

15. BPC: Art and Computation – Summer 200715 arp script example: basic sequence arp 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

16. BPC: Art and Computation – Summer 200716 darp 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

17. BPC: Art and Computation – Summer 200717 arp example: change object size arp 2.0 name benThorn_seq geom_path./ playspeed 4 sound_path../configs/ frame geom_scale 0.56 0.56 0.56 geom_show btw1.obj frame geom_scale 0.42 0.42 0.42 geom_show btw1.obj frame geom_scale 0.56 0.56 0.56 geom_show btw1.obj frame geom_scale 0.7 0.7 0.7 geom_show btw1.obj

18. BPC: Art and Computation – Summer 200718 Design decision - sound clips Simplicity Gives simple import methodology Allows input from many tools Uses commonly available format (.aiff)

19. BPC: Art and Computation – Summer 200719 Example - 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.aif frame geom_show clustergeom0001.obj sound_xyz_stereo 187.016266 -157.446847 -103.679324 174.847813 -43.615647 -103.679324 sound_move h2o4.aif frame geom_show clustergeom0002.obj sound_xyz_stereo 193.031556 -156.477695 -103.679324 168.832524 -44.584799 -103.679324 sound_move h2o4.aif

20. BPC: Art and Computation – Summer 200720 The view frustum What you actually see Units matter (DAFFIE uses feet)

21. BPC: Art and Computation – Summer 200721 Navigation - user experience The 6 degrees of freedom How map onto various input devices Communication with viewer (old model) –direct sending of xyz,hpr wand motion to viewer

22. BPC: Art and Computation – Summer 200722 The DAFFIE event system Communication between agents

23. BPC: Art and Computation – Summer 200723 Triggering objects Light stick (by viewer) Proximity (by viewer) Proximity (by agent) Other (by agent) The trigger event

24. BPC: Art and Computation – Summer 200724 World state and events Object descriptions Trigger Transforms Switches Navigation Sound Video Etc.

25. BPC: Art and Computation – Summer 200725 Agents and events Using events to control elements of the world –Triggering sequences –Moving objects –Changing rooms –Navigation

26. BPC: Art and Computation – Summer 200726 Navigation by agent sending events New model - sending of transform matrices to viewer Keeping track of avatars

27. BPC: Art and Computation – Summer 200727 Telephony 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

28. BPC: Art and Computation – Summer 200728 Video texture maps Video as sequence of images Video generator –Sends sequence of images Viewer –Receives sequence of images –Uses texture mapping on an object in scene

29. BPC: Art and Computation – Summer 200729 Stereo 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

30. BPC: Art and Computation – Summer 200730 Tiled walls Issues and differences –Head node vs render nodes –Event management / avatars / triggering –Virtual cameras –Alignment

31. BPC: Art and Computation – Summer 200731 The End