[Bf-committers] Proposing a unique ID for Blender objects system, for use with game engines.

Scott Wilson gdragonmtn at gmail.com
Fri Nov 13 02:51:03 CET 2020

That's only valid for the lifetime of the object, though (it uses the
memory location of the object). If you restart Blender, delete the Python
object, or create a new Python object that points to the same memory in C,
then all the IDs will likely be different for the same object in C. Also,
the C objects' memory locations will likely change between Blender
restarts, and deletions.

On Thu., Nov. 12, 2020, 5:20 p.m. AMDBCG via Bf-committers, <
bf-committers at blender.org> wrote:

> Python has an id for each object that can be referenced in your Blender
> importer
> https://www.programiz.com/python-programming/methods/built-in/id - where
> id is the main id of the object
> -Robert Fornof (amdbcg)
> On 11/12/2020 9:24 AM, Juan Linietsky via Bf-committers wrote:
> > Hi guys, lead Godot dev here.
> >
> > I wanted to discuss with you a problem we are often having that I am not
> > certain how it can be solved entirely from our side, I add a proposal for
> > this, but if you guys have a better recommendation, I'm very open to any
> > ideas.
> >
> > Basically, Godot will import scenes (GLTF/FBX/DAE/etc) as they come from
> > blender, and it generates the same object names, resource names, etc. as
> > they come from Blender and the resource file.
> >
> > We use the same names so we can keep track of changes in the Blend file.
> If
> > an object is moved, a material is changed, etc. we detect on re-import
> and
> > everything is updated in Godot.
> >
> > This is especially more annoying in Godot than in other game engines,
> > because Godot can read the whole Blender scene and keep it more or less
> > intact, so users love using this for level design workflow (so they can
> > design levels in Blender).
> >
> > So, the problem is that it often happens that for some reason, artists
> want
> > to rename the objects in Blender. Be it because they didn't care at the
> > beginning and they want to become more organized later, or because the
> > scene became bigger and they need to make their naming of things more
> > precise to navigate it around. In this situation, when something is
> renamed
> > on the Blender side and re-exported, the game engines have no idea where
> > this object went, so we need to either remove it (resulting in loss data)
> > it or orphan it (resulting in duplicated data).
> >
> > While I do think that good practices solve this and this is probably not
> > such an issue in a professional environment, truth is that game
> development
> > has become a huge hobbyist activity, and our users find this situation
> > constantly and are annoyed with it, and there is nothing we can do from
> our
> > side.
> >
> > The obvious proposal to solve this would be to ask Blender whether it's
> > possible to generate a unique object ID (UUID?) and make sure it does not
> > change over time even if objects are renamed, then changing the
> exporters a
> > bit to (optionally if selected in the export settings) add this
> information
> > as extensions in the existing format (on GLTF it should be rather easy).
> >
> > If you guys think this is possible, it would be very helpful for us, if
> you
> > have other ideas on how we could solve this, we are very open to
> discussion.
> >
> > Best
> >
> > Juan
> > _______________________________________________
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