Geometry and Physics VAG

(this is an initial draft so scope and focus are still fairly open. Please add comments to the Talk:Geometry and Physics VAG if you have slightly different viewpoints so we can try to converge on a common view. This discussion could also expose other similar VAG that are needed in this area --Burhop Piccard 18:38, 16 October 2007 (PDT) )

Purpose

The Geometry and Physics Viewpoint Advocacy Group exists to provide input for architectural design that is focused on the (virtual) physical modeling of objects.

See the Architecture Working Group and the Viewpoint Advocacy Groups for more information.

List of concerns addressed by this viewpoint

Areas of concern addressed by the viewpoint include:

• Describing the physical shape of the object.
• Describing the physical and material properties of the object (mass, color, material, surface texture).
• Efficient comunication of Geometric and physical properties.
• Use of open standards that allow for predictable sharing of data with various systems and tools
  • Creation of data using various 3D modeling tools (i.e. Maya, Sketchup, 3D CAD, etc.)
  • Reading of data by other software (other VW's, design and modeling tools, physics engines).

Areas not addressed by this viewpoint

• Display is not addressed by the viewpoint. This is expected to be a fairly complex topic posibly involving differnet viewers and display technologies. Another VAG is needed for this.

• Specific technologies and applications are not specifically part of this viewpoint. That is, this view is one of open archtecture capable of working with multiple applications and tools.

Use Cases

See the Architecture Working Group Glossary and usecase templates for more information on creating usecases. One liners are fine (and better than nothing) but more detail will result in a better understanding and a better architecture.

• Direct Creation in Second Life
  • Direct Creation from Maya
  • Direct Creation from Blender
  • Direct Creation from Surface based modelers (please split for specific tools)
  • Direct Creation from Solid Modelers (3D Mechanical CAD - please split for specific tools)
  • Direct Creation from User built External Tools (i.e. such as showed up with Sculpted Prims)
  • Direct Creation with User build in-world tools

• Geometry Import - File Format
  • Import from Collada
  • Import from OBJ
  • Import from JT
  • Import from 3DM

• Direct Geometry data transfer between Virtual Worlds
  • Geometric asset exchange with other AWG based Asset Servers
  • Geometric asset exchange with MPK20 (Sun)
  • Geometric asset exchange with (who else wants to exchange data with SL? WOW? Metaverse? )

• Viewer scalability use cases
  • High Fidelity graphics with High Power Computer
  • Low Fidelity graphics with Low Power CPU (i.e. Cell phone)
  • Viewer on low bandwidth computer
  • Viewer accessing region with large amount of geometric data

• Physics Use Cases
  • Mars (or other planet) virtual world/region support
  • Underwater virtual world/region support
  • Space (no gravity) based virtual world/region support
  • non-unidirectional gravity for the whole sim, eg 'floor is the inside of a sphere'

Related JIRA Issues

The following JIRA issues are known problems that this VAG would like to see resolved in any future architecture. The purpose of this list it to avoid problems that exist in the curent architecture. The more typical JIRAs that are more short term in nature or can be resolved by simple code or design change should not be listed here.

• SVC-73 Request for subtractive prims and holes
• VWR-858 Ability to import 3DM files
• VWR-1110 Ability to Import .OBJ Files
• VWR-1387 Ability to import .JT files
• VWR-2527 Ability to Import .DXF Files
• SVC-814 New prim type: Geometric prim
• VWR-2547 new prim type: ropes
• VWR-2260 Polygons Clean-up Issue (a bit outdated)
• SVC-885 Physic address to prim gap/overlaps issue for vehicles.

Organization

Joining

Anyone with an interest in this Viewpoint is welcome to join. You should join the AW_Groupies group in Second Life.

In world meetings

We meet once a week in-world and more if people are available.

Also members are active on the wiki and in the SLDEV mailing list.

Meetings are scheduled via the "SL AW Groupies" google calendar"

Meeting Agendas

• TBD

Chat Logs

• TBD

Modeling Techniques used to express viewpoint

None decided.

Architecture (Geometry View)

See here for the Geometry Based Architecture View

Some Comments on generality of geometries

External Links

• Geometry
  • Obj format
  • Collada
  • JT Open
  • Constructive Solid Geometry (CSG) http://gts.sourceforge.net/ http://www.cgal.org/ http://opencsg.org/
  • Universal 3D Standard (U3D) http://www.intel.com/technology/systems/u3d/ http://www.ecma-international.org/publications/standards/Ecma-363.htm
  • X3D - ISO standard for delivering realtime interactive 3D graphics over the web

• Physics
  • Havok
  • PhysX Ageia

Members (Stakeholders)

Burhop Piccard - Founder

Morgaine Dinova - Analyst (scalability aspects)

Wyn Galbraith - Builder & Prim Torturer

Hypatia Callisto - 3d Artist

JeanRicard Broek - Licenced Architect, GIS, SL Builder

Vincent Nacon - 3d Artist, Marketing Strategist, SL Builder & Scripter

Seifert Surface - Mathematician, 3d Artist, Scripter