[ODE] XML Formats

Justin Couch justin at vlc.com.au
Tue Feb 6 13:13:02 MST 2007

Jon Watte (ODE) wrote:
> There is a bit of support for physics in X3D, but not enough to be 
> authoritative from what I've seen.
> Another XML format that I see being popular in games (in fact, more 
> popular than X3D), is Collada (www.collada.org).

As one of the spec authors of X3D (and previously VRML97) let me toss my 
2c in here. My business partner is president of the Web3D consortium, 
and also sits on the Collada standards group a Khronos.

X3D has very different goals to Collada. X3D is designed around long 
term data storage and data interchange. There is also a large amount of 
interactivity stored. Collada is designed around the needs of static 
geometry import.

One of the very key differences between the two formats is that Collada 
has version history, but X3D does not. That is, you can open a Collada 
document and see every single version that model has gone through 
whereas in X3D you only get whatever was just saved.

The second key difference is that Collada does not have a runtime model, 
X3D does. X3D is a complete environment in that way, whereas Collada 
assumes that you are importing the information into some other runtime 

X3D has a rigid body physics component. I wrote it. I based it almost 
entirely on the design of ODE, but with some references to the other 
various APIs out there. There's a few minor differences, but not enough 
to be of issue.

If you wanted to choose X3D for a file format, then your best bet would 
be to say "Interchange profile plus rigidbody physics component". Don't 
even attempt to look at anything higher than that as then you'll have to 
deal with all the really gnarly stuff like the event model, scripting 
and so forth.

If anyone wants to discuss further the details between those two, let me 
know and I can spew forth lots of useless info as I'm more than aware of 
the intricacies of the two formats :)

Justin Couch                         http://www.vlc.com.au/~justin/
Java Architect & Bit Twiddler              http://www.yumetech.com/
3D Java Graphics Information                    http://www.j3d.org/
"Look through the lens, and the light breaks down into many lights.
  Turn it or move it, and a new set of arrangements appears... is it
  a single light or many lights, lights that one must know how to
  distinguish, recognise and appreciate? Is it one light with many
  frames or one frame for many lights?"      -Subcomandante Marcos

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