3D Data - What comes next?



Problems of presenting three-dimensional data in the web. Work in progress

Sebastian Schröder (MPIB) and Jörg Kantel (MPIWG),
November 12, 2009

Motivation

  • MPIWG: 3D data representing cuneiform tablets
  • MPIB: 3D data produced from CRT-scans and the threedimensional presentation of brain activities

Motivation (cont.)

We want this in 3D!

Problem (1)

  • 3D data are given (in our case: PLY or VRML formats)
  • 3D data are too big (more then 120 MB)
  • Therefore it is nearly impossible to show them on the web
  • Loading such data locally in a viewer also makes problems

Problem (2)

  • There are many different formats used by different applications
  • this leads to isolated solution for presenting, archiving, and manipulating the data

Use Cases

Goal (1)

  • One open format for archiving
  • One (open) format for presenting the data on the web as well as on the desktop
  • One format for data processing and exchange

Fragebogen?

Goal (2)

  • Simple linking to metadata
  • (integrated in the 3D dataset or stored separately?)

Basic approach

  • Open archive format: PLY, VRML
  • Format for presentation: PDF, Flash or QuickTime VR
  • Format for processing and exchanging data: Cinema4D, an Autodesk format such as 3ds-Max (.3ds), or X3D (the W3C standard)

Presentation

  • Creating thumbnails for the web
  • The possibility of downloading in full resolution
  • Presentation using a desktop viewer

The Breuckmann solution

final72.jpg

The Breuckmann solution (cont.)

  • OptoView (Fa. Breuckmann)
  • Free as in free beer (not open source)
  • Reads PLY
  • The possibiliy of setting multiple lights easily
  • Sufficiently fast
  • Windows only

The Meshlab solution

MashLab

MeshLab is a open source viewer for Windwos, Linux, and MacOS X (Intel only)

Meshlab (cont.)

  • Not really usable for big Meshes (Thanks, Matteo!)
  • Reads PLY
  • Only one light

Exkurs: PLY -> VRML or PDF

  • There are problems reading the PLY format into Cinema 4D
  • The computer crashes when reading PLY files
  • Next approach:
  • Converting PLY to VRML using Cinema 4D
  • Program hangs during the convertion process (possibly due to the file size)

PLY -> PDF (cont.)

  • Next approach:
  • Converting PLY to PDF using Acrobat Professional Extended 9
  • Computer crashes (out of memory)

VRML (cont.)

  • Next approach:
  • The Breuckmann software converts PLY to VRML extremely fast and without problems

PDF (cont.)

  • Next approach:
  • Converting VRML to PDF using Acrobat Professional Extended 9
  • Again »out of memory« using a computer with 6 GB of main memory
  • Only a computer with a 64 Bit system and 20 GB main memory could be used successfully

No Textures

  • The problem still exists that textures seem to be systematicelly ignored (we are elaborating the problem)

VRML and Cinema 4D

  • Next approach:
  • Importing VRML into Cinema 4D
  • Cinema 4D reads VRML files without any problems
  • Our guess: Since Cinema4D has been developed for movies and animations it is better prepared for reading big files than other tools

Cinema 4D

Why Cinema 4D?

  • Cinema 4D offers many import, export, and conversation facilities
  • But: Cinema 4D looses the textures (colours)
  • If we could manage Cinema 4D to import the VRML files with textures, then we would have a good starting point for the export in various other formats (we are working to fix that problem)

Cinema 4D -> QuickTime VR

  • Next approach: Converting files from Cinema 4D to QuickTime VR
  • Needs a lot of computing power but Cinema 4D is able to use all existing cores

Using PDF

  • Advantage: Very small files: 160 MB VRML is compressed to 4 MB PDF
  • Therefore, PDF provides a good basis for the representation on the web
  • There are free viewers and free plug-ins for all common browsers
  • Offers the possibility to set one light only, but it can be coloured

Using PDF (cont.)

  • Very slow on older Macintosh computers (PPC architecture)
  • PDF has the possibility to attach metadata to every 3D point
  • nearly lossless compression due to the real-time rendering engine

PDF plug-in for browsers

3D PDF im Safari

PDF with a desktop viewer

3D PDF im Adobe Reader

(with coloured light)

QuickTime VR Screenshot

Screenshot QuickTime VR

QuickTime VR

  • average file size: 160 MB VRML is compressed to a 20 MB QuickTime VR Movie
  • QuickTime VR looses information due to pre-rendering the images and also due to the codecs
  • QuickTime plug-in available for all Windows and MacOS X browsers
  • No possibility to set any lights. But there is a standard light source with pre-rendered light and shadow sequences
  • QuickTime Panorama provides the possibility for 360°-movies (not relevant for cuneiform tablets)

VRML and FreeWRL

VRML and FreeWRL (cont.)

  • FreeWRL is a free (as free as in freedom) desktop viewer for VRML/X3D. It runs under Linux and MacOS X. A port for Windows is since a long time »in preparation«.
  • FreeWRL is at the moment the only VRML viewer that displays the textures.

VRML on the web

  • As far as we know there are currently only VRML browser plug-ins for Windows
  • But our VRML files are in any cas to big for the web
  • Therefore our approach for using VRML files (as for PLY files) is to offer the possibility to download them in order to use a desktop viewer

Testing activities in progress

  • Google SketchUp
  • 3D Studio Max
  • AutoCAD products (DXF)
  • Flash-3D-Engine for 3D-web-»thumbnails«

Current preliminary strategy

  • Presenting the two-dimensional 6-side view on the web
  • Simultaneously presenting a 3D-»thumbnail«
  • Offering downloads as PLY and VRML files
  • Providing metadaten separately as XML file

?

  • Do you have any further ideas or suggestions?

Thanks


Werbung