[cgma-dev] Switching unique IDs to RFC4122 UUIDs

[David Thompson]

Hi Clinton,

>>> I am looking into switching CGMA's IDs from ints (4-8 bytes, signed) to
>>> RFC4122-style UUIDs (16 bytes, unsigned) so that cross-references across
>>> multiple large models are much less likely to have duplicate IDs.
> 
> Keeping track of the current file and entities being read is a good approach.

Yes, but something we want is an ID that can reference entities which may be in multiple files. Tracking the current file with an integer defined by the load order doesn't provide a way to do that.

> Even if you have a better unique id (e.g. RFC 4122), you will still have 
> collisions when importing the same file twice.

Actually that should not happen with RFC 4122 UUIDs as all the variants use a random number generator seeded with something involving the current time (or use the time directly in the UUID).

> By the way, its nice to see Kitware using CGM.  I'm curious what its being used for.

We are looking at it for a modeling and simulation workflow framework.

	David