Talk:Ifd:Second LexiCon-BARBi Unification workshop

On the topic of (parametric) geometric model inclusions
In this section OpenGL is being proposed as a possible means to store parametric 3D geometries in IFD. U3D is being mentioned as another candidate means. My two cents:


 * 1) Capturing truly parametric geometries is a highly non-trivial field
 * 2) many approaches to do this have been worked upon by hundreds of engineers since the early days of CAD. Many promising ones have died a painful death along the way.
 * 3) We do not have the (human and knowledge) resources to come up with s.th. 'from scratch on our own within a year
 * 4) bad news:
 * 5) 'pure and naked' OpenGL is definetly not an option. It's not even somewhere near a file format or storage, it's simply "a software interface to graphics hardware" ( from the OpenGL spec ).
 * 6) allthough there are some graphic primitives defined in the OpenGL Utility Toolkit (GLUT) like box, cone etc., it's still nowhere near what is needed for parametric objects.
 * 7) good news: there are many approaches, existing initiatives and people working on this:
 * There are vendor specific implementations of parametric objects, like [Graphisoft's GDL] and others
 * Plus:
 * it works
 * Minus:
 * vendor-specific
 * outdated
 * pretty horrible to code if you ask me

--Jakob.Beetz 17:24, 4 May 2006 (CEST)
 * There is X3D and VRML97 who have a very powerful PROTOTYPEing mechanism (that can be connected to ECMAsrcripting, hence making things like DoorWidth=DoorHeight/2 and more complex procedural things possible)
 * Plus:
 * it's XML with an optional binary compressed version.
 * it's open.
 * many existing tools, libraries, viewers.
 * Minus:
 * not much support for standard CAD vendors
 * Somthing is happening within STEP / ISO 10303 : part 108: "Parameterization and constraints for explicit geometric product models". I have no idea, where they currently are, but maybe it's worth having a closer look at this and maybe try to get in touch with the guys (Michael J. Pratt seems to be the driving force here, I will browse through some of his publications. A free available paper (thoug somewhat old) covering the basics is here. If you have access to Elsevier, there is a recent one here).