[vos-d] web3d symposium report

[Reed Hedges]

A3DL is not radically different from the X3D node model; it's simplified in a
few places, and also does not contain as many object (node) types. We used
VRML97 for some inspiration.  It also has a few bits that reflect the 
capabilities of CrystalSpace.

Look at the libmetaobject_a3dl API documentation to see it.  
http://interreality.org/static/docs/api-html/namespace_a3_d_l.html

In short, it's like this. Each vobjcet can be shared with other vobjects too. In
VRML97 if you DEF and USE a node, it becomes one Vobject shared in each USE
context. 

* a3dl:object3d - base type
 * position (x,y,z)
 * orientation (ox,oy,oz,angle)
 * scaling (x,y,z)
 * hardscaling (x,y,z) - scales vertices before rendering
 * material
   * color
   * transparency (default)
   * blend mode (default for mixing with other objects if trasparent - normal alpha, add, multiply)
   * texture
     * bitmap image data
     * alpha value 
     * blendmode 
     * shaded  - whether to do smooth shading on this texture layer or not
     * transparent keycolor - color to instead render as alpha=0
     * texture mapping offset (u,v)
     * texture mapping scaling (u,v)
   * texture
     * ...
   * texture 
     * ...
   * ... any number of texture objects for texture layers ...
 

* a3dl:object3d.cube, cylinder, cone, sphere - "primitive" shapes
  these have all the same properties as the base object3d. 

* a3dl:object3d.polygonmesh - general mesh type, like IFS in VRML. 
to the base type, it adds:
 * vertices - vertex positions
 * polygons (faces) - index into vertices
 * texturemapping
  - indexes into faces and texture channels
  - there are a couple of different ways to specify texturemapping, see
    A3DL::PolygonMesh docs for details
 * doublesided flag

* a3dl:light - point light
 * position
 * radius
 * color

* a3dl:object3d.billboard
 * ...
 * material
  * texture... etc. just like base object3d
 * ...

* a3dl:object3d.viewpoint

* a3dl:object3d.portal - discussed elsewhere recently on this list

* a3dl:sector - container for a "scene"


Reed


On Thu, Apr 27, 2006 at 02:35:05PM +0200, Benjamin Mesing wrote:
> Hello,
> 
> > So, while I was at the conference and surrounded by the X3D vibe, I was 
> > seriously considering throwing out A3DL in favor of a new set of object 
> > types that were more literally based on the X3D object model and taking 
> > VOS in a whole new direction of being a multi-user X3D browser.  Having 
> > had a chance to think about it some more and to talk to Reed and Kao and 
> > others on IRC, I have decided maybe that is not such a good idea :-)
> I don't really know A3DL, but could you provide a rational why X3D is
> not suitable, or A3DL is the better solution?
> 
> Best regards
> 
> 
> 
> 
> _______________________________________________
> vos-d mailing list
> vos-d at interreality.org
> http://www.interreality.org/cgi-bin/mailman/listinfo/vos-d