[Bf-committers] Collada importer/exporter kickout

Alexandr Kuznetsov kuzsasha at gmail.com
Sat Jan 7 20:33:13 CET 2012


Hi Erwin.

I don't think .blend importer is very good idea. We need a 3D format like
.png for images because it makes easier to share projects between programs.
There is probably 10-20 major programs which people use with Blender. So,
writing for each of them an extension for .blend importer is not realistic.
In addition, the implentation will be very basic due to their quantity.
Another problem is .blend format. .blend is essentially a dump of blender's
program memory. It has useless data like different preferences and other
internal data which intended for blender use only. Moreover, there is no
standard for .blend file. File format is constantly evolving. Therefore C
importer must constantly reflect changes and so the plugins.
It is better to have a very solid importer/exporter for universal 3d
format. If there is no good opensource library, it is better to write it
ourselves, rather then to support 20 importers/exporters different quality.

Best Regards,
Alex


On Sat, Jan 7, 2012 at 2:16 PM, Erwin Coumans <erwin.coumans at gmail.com>wrote:

> @Morton
>
> A C++ .blend importer may not be a viable alternative for some people
> (artists)
> but using an existing open source C++ .blend importer can be a viable
> alternative for programmers.
>
> It would be great to have well maintained COLLADA export/import for Blender
> of course,
> so good luck if someone can create and maintain a Python implementation.
>
> Peter Amstutz wrote
> >> When I looked last looked at OpenCollada, one critical issue preventing
> >> someone else from taking over maintenance is the fact that it relied
> >> heavily on autogenerated code, but the code generator and the input file
> >> are not included in the online repository.
>
> That is a serious issue. Did someone try to make those code generation
> files available?
>
> >> There would also needs to be a set of test cases,
>
> Khronos/COLLADA workgroup has an extensive conformance tests,
> unfortunately they are only available to members. If someone starts
> maintaining
> OpenCollada, they probably can get access to those conformance tests.
>
> Thanks,
> Erwin
>
>
> On 7 January 2012 09:47, Morten Mikkelsen <mikkelsen7 at gmail.com> wrote:
>
> > Erwin I consider this irrelevant in the current discussion. Programmers
> > should they choose to can write .blend importers
> > but the current discussion is what to do about collada for blender.
> Telling
> > everyone to write .blend importers (incl artists) is not
> > a viable alternative.
> > That being said it sounds like Juan has a good start here.
> >
> >
> >
> >
> > On Sat, Jan 7, 2012 at 9:23 AM, Erwin Coumans <erwin.coumans at gmail.com
> > >wrote:
> >
> > > You are right that in some cases an exporter is better, but in many
> cases
> > > a C/C++ .blend importer is a better to go.
> > >
> > > I just wanted to remind anyone reading this thread that
> > > there is an easy way to extract any data from Blender in C++,
> > > including animation curves, skinning info, textures etc,
> > > without the issues of COLLADA and FBX.
> > >
> > > I'm not familiar with baking,
> > > but you might be able to store the baked data in the .blend file.
> > >
> > > Thanks,
> > > Erwin
> > >
> > >
> > >
> > > On 7 January 2012 09:10, Juan Linietsky <reduzio at gmail.com> wrote:
> > >
> > > > Erwin,
> > > >    That looks awesome and really useful, however the main advantage
> of
> > an
> > > > importer is the ability to bake everything (IK and other constraints)
> > > just
> > > > like it's displayed in Blender.
> > > >
> > > > Cheers
> > > >
> > > > Juan Linietsky
> > > >
> > > > On Sat, Jan 7, 2012 at 2:07 PM, Erwin Coumans <
> erwin.coumans at gmail.com
> > > > >wrote:
> > > >
> > > > > Instead of going through the COLLADA or other intermediate format
> > > > > you can directly extract any data from a .blend using this C++
> .blend
> > > > > parser:
> > > > >
> > > > > http://tinyurl.com/6s7k9zw
> > > > >
> > > > > AnimKit with the .blend loader includes a small sample that loads a
> > > > .blend
> > > > > file,
> > > > > extracts textures, meshes, animations, skinning and physics info.
> > > > > It shows a skinned skeletal animated character using AnimKit and
> GLUT
> > > > > (keeping dependencies to a minimum)
> > > > >
> > > > > Cheers,
> > > > > Erwin
> > > > >
> > > > >
> > > > > On 7 January 2012 07:38, Morten Mikkelsen <mikkelsen7 at gmail.com>
> > > wrote:
> > > > >
> > > > > > In my case I do not need morphs. I do need animation and skinning
> > > > though.
> > > > > > And obviously
> > > > > > also geometries and materials. And it sounds like you have this
> > > > covered?
> > > > > > I have no sense of loyalty toward OpenCollada so if this is a
> > viable
> > > > > > solution
> > > > > > I am for it. Can you make it available somewhere with
> instructions
> > on
> > > > how
> > > > > > to install it so people can test it?
> > > > > >
> > > > > > Cheers and thanks,
> > > > > >
> > > > > > Morten
> > > > > >
> > > > > >
> > > > > > On Sat, Jan 7, 2012 at 7:06 AM, Juan Linietsky <
> reduzio at gmail.com>
> > > > > wrote:
> > > > > >
> > > > > > > Hi guys,
> > > > > > >
> > > > > > >    I made my own Collada exporter in Python and that's what
> I've
> > > been
> > > > > > > using. It's less than 1k lines of code and does not depend upon
> > any
> > > > > > library
> > > > > > > or anything, but it exports everything except morphs. I don't
> > have
> > > > much
> > > > > > > time to work on it at the moment, but it's so simple and
> complete
> > > > that
> > > > > if
> > > > > > > anyone else want's to work on it, it should be really easy. I'm
> > > also
> > > > > not
> > > > > > an
> > > > > > > expert at Python or Blender API so someone more experience can
> > > > probably
> > > > > > > shape it up better. It's also much more stable than the
> official
> > > one
> > > > > (due
> > > > > > > to it being so small).
> > > > > > >
> > > > > > > Feel free to do anything with it or integrate it into Blender,
> > just
> > > > > > credit
> > > > > > > me on the file. I would love to work more on it, or even make a
> > > > proper
> > > > > > > importer since I have a high level of expertise in Collada,
> but I
> > > > have
> > > > > > very
> > > > > > > little time and must work to earn my meals.
> > > > > > >
> > > > > > > Cheers!
> > > > > > >
> > > > > > > Juan Linietsky
> > > > > > >
> > > > > > >
> > > > > > > On Sat, Jan 7, 2012 at 11:49 AM, Morten Mikkelsen <
> > > > > mikkelsen7 at gmail.com
> > > > > > > >wrote:
> > > > > > >
> > > > > > > > Yes that's a very relevant point. A collada solution with
> just
> > > > > > positions,
> > > > > > > > UVs and normals
> > > > > > > > is not a solution. In that case you might as well use obj
> > format.
> > > > > > > > I went through the hard work of writing a collada importer
> > > > > specifically
> > > > > > > to
> > > > > > > > get skinning and animation
> > > > > > > > into my tech frame-work.
> > > > > > > >
> > > > > > > >
> > > > > > > > On Sat, Jan 7, 2012 at 5:03 AM, skoti <skoti48 at o2.pl> wrote:
> > > > > > > >
> > > > > > > > > I know Collada importer / exporter is problematic (I wrote
> an
> > > > > > importer
> > > > > > > > > for my engine and I know that everything in the Collada can
> > be
> > > > > stored
> > > > > > > in
> > > > > > > > > N different ways).
> > > > > > > > >
> > > > > > > > > - If you want to use the model in Second Life / Google
> Earth,
> > > you
> > > > > > have
> > > > > > > > > to use Collada, if you want to use models in engines
> > > > WebGL/Flash3D
> > > > > > > > > practically have to use Collada (is there any web engine
> with
> > > FBX
> > > > > > > > > importer?), Most game engines use Collada for importing
> data
> > > > > (support
> > > > > > > > > for FBX a few). FBX exporter also has bugs. Well, that FBX
> is
> > > in
> > > > a
> > > > > > > > > blender, but it is not usually an option for people using
> > > > Collada.
> > > > > > > > >
> > > > > > > > > - If someone uses Collada it not for the base mesh + uv
> (then
> > > > using
> > > > > > *.
> > > > > > > > > obj) and for skeletal animation, lights, cameras and their
> > > > > animation
> > > > > > > > > (motion, color, light and their intensity), multiUV (uv for
> > > > color,
> > > > > > > > > normalmap ... + uv for lightmap). And all this in current
> > > Collada
> > > > > > > > > exporter works well.
> > > > > > > > >
> > > > > > > > > - No other exporter does not work here as well as Collada -
> > ofc
> > > > has
> > > > > > > > > bugs, but it has nothing what could replace the Collada in
> > this
> > > > > task.
> > > > > > > In
> > > > > > > > > the future, Alembic can replace Collada, but not for
> several
> > > > years.
> > > > > > > > >
> > > > > > > > > IMO, better to leave Collada, until you will be able to
> > replace
> > > > it
> > > > > > with
> > > > > > > > > success to other formats like Alembic (FBX is not popular
> in
> > > the
> > > > > > > > > software and you can not replace him Collada in most
> tasks).
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On 7 Jan, 2012, at 12:30, Ton Roosendaal wrote:
> > > > > > > > > > Hi,
> > > > > > > > > >
> > > > > > > > > > I realize the proposal was harsh, but it was meant as a
> > > public
> > > > > > > > statement
> > > > > > > > > as well (to khronos, opencollada team, etc). I don't want
> to
> > > > blame
> > > > > it
> > > > > > > on
> > > > > > > > > the hard working devs here. We do have collada IO work at
> > some
> > > > > level,
> > > > > > > and
> > > > > > > > > that has been proven useful in several cases. The job is
> just
> > > > > > > incredible
> > > > > > > > > hard to achieve.
> > > > > > > > > >
> > > > > > > > > > To move forward:
> > > > > > > > > >
> > > > > > > > > > - userts who successfully applied .dae could also check
> > > whether
> > > > > > > another
> > > > > > > > > exchange format would have done the job as good. Tried FBX?
> > > > > > > > > >
> > > > > > > > > > - note that for basic mesh (+uv) export, a quite simple
> > > script
> > > > > > could
> > > > > > > do
> > > > > > > > > the job already. It is probably a few days job for a py
> > > scripter.
> > > > > > > > > >
> > > > > > > > > > - we are currently including about 100 MB of opencollada
> > libs
> > > > to
> > > > > > > make a
> > > > > > > > > feature work that's meant to be able to exchange (I+O) full
> > > shots
> > > > > or
> > > > > > > game
> > > > > > > > > environments, with character animation and so on. That's
> what
> > > > > Collada
> > > > > > > was
> > > > > > > > > designed for, and that's a target we can't support.
> > > > > > > > > >
> > > > > > > > > > -Ton-
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > ------------------------------------------------------------------------
> > > > > > > > > > Ton Roosendaal  Blender Foundation   ton at blender.org
> > > > > > > > www.blender.org
> > > > > > > > > > Blender Institute   Entrepotdok 57A  1018AD Amsterdam
> The
> > > > > > > Netherlands
> > > > > > > > > >
> > > > > > > > > > On 6 Jan, 2012, at 21:21, Morten Mikkelsen wrote:
> > > > > > > > > >
> > > > > > > > > >>> 1) Official announcement that Blender drops Collada
> > support
> > > > > > > > > >>> 2) Move Collada support into a branch, out of trunk
> > > > > > > > > >>> 3) Create a tracker "orphanage" or "branches" or so,
> > where
> > > we
> > > > > put
> > > > > > > all
> > > > > > > > > >>> reports that are not in support (anymore).
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >> I just want to say though I am not up for the challenge
> of
> > > > > taking
> > > > > > > over
> > > > > > > > > on
> > > > > > > > > >> this sub project I would be sad to see Collada support
> > taken
> > > > out
> > > > > > of
> > > > > > > > > trunk.
> > > > > > > > > >> I use it often also with skinning export. I know many
> > users
> > > do
> > > > > and
> > > > > > > > > >> eventhough I understand everyone's frustration I prefer
> > the
> > > > > > > > > implementation
> > > > > > > > > >> that is there now (which I use often) to no built-in
> > version
> > > > at
> > > > > > all.
> > > > > > > > > >>
> > > > > > > > > >> I am not disagreeing with any of the frustrating aspects
> > of
> > > > > > Collada
> > > > > > > > > which
> > > > > > > > > >> you and others have mentioned.
> > > > > > > > > >> Just saying personally I do use it and would very much
> > like
> > > to
> > > > > > keep
> > > > > > > it
> > > > > > > > > in.
> > > > > > > > > >> With bugs and all :)
> > > > > > > > > >>
> > > > > > > > > >> I have seen many other commercial tools with awful
> crappy
> > > .3ds
> > > > > > > > importers
> > > > > > > > > >> and exporters but bad as they were they didn't take them
> > out
> > > > > > > > > >> because people were still relying on them and using
> them.
> > > > > Despite
> > > > > > > the
> > > > > > > > > bugs
> > > > > > > > > >> in them.
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> Cheers,
> > > > > > > > > >>
> > > > > > > > > >> Morten.
> > > > > > > > > >> _______________________________________________
> > > > > > > > > >> Bf-committers mailing list
> > > > > > > > > >> Bf-committers at blender.org
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