[Bf-python] OpenCollada Documentation?

[Khalifa Lame]

Thanks very much Toni. I got in touch with one of the OpenCollada devs. He
also advised me to stick with my C# code.

I continued on with C# but, while testing today, the results were less than
encouraging. It's painfully slow to load meshes with more than a few
thousand polygons. I haven't gotten to the bottom of it yet, but I think
it's down to the very nature of collada data. The data is stored in a raw
form and one has to calculate just about everything manually. From normals
to share vertices, etc. These calculations seem to scale exponentially with
model complexity.

Some months back, I invented my own xml-based 3d format where everything is
pre-calculated before being written to file. I've been using that to
save/load 3d scenes within the app. It looks more and more likely that I'll
have to write a blender exporter for that format rather than using collada.
Fingers crossed, that should fix the long waits when loading models.

Thank you very much.

On Sun, Jul 24, 2016 at 6:03 PM, Toni Alatalo <toni at playsign.net> wrote:

> OpenCollada is a C++ library that Blender indeed uses.
>
> I don't think there is any secret documentation, just what they have in
> github to describe the parts of their code repository
> https://github.com/KhronosGroup/OpenCOLLADA/#directories . Then you can
> read the C++ sources to see what's there, for example this tells how you
> can get mesh information:
> https://github.com/KhronosGroup/OpenCOLLADA/blob/master/COLLADAFramework/src/COLLADAFWMesh.cpp
>
> It is possible to use C++ libraries in C# code but can be simpler for you
> to just add what you need in your code. Both because using C++ in C# adds
> complexity and indeed because OpenCOLLADA is not so documented and
> reportedly (have no experience myself) painful to work with.
>
> Khronos is now active with glTF which has been adopted by some companies
> and projects. It is JSON + binary data instead of XML. Work there is active
> on many fronts so if you want a bandwagon to jump on it can be a good
> choice, depending what you need (glTF is to have small files to transfer,
> unlike COLLADA which was made for interop between apps using bigger files).
> They are marketing it here at SIGGRAPH now, gave t-shirts yesterday and
> sponsor a lunch to talk about it here at the web3d event where am now :)
> https://github.com/KhronosGroup/glTF
>
> But again if you already have things working with your own .net XML code
> it can be simplest to just add what you need there, depends on the
> specifics.
>
> ~Toni
>
> On Sun, Jul 17, 2016 at 10:58 PM, Khalifa Lame <khalibloo at gmail.com>
> wrote:
>
>> Hello. I've been working with collada files on a personal project for a
>> while now. I wrote an importer using an xml parser. Now everything works
>> fine, but I'm considering upgrading to OpenCollada SDK in order to take
>> advantage of some advanced features that would take ages to develop on my
>> own.
>>
>> Honestly, I'm not even sure what OpenCollada is... let alone how to use
>> it.
>> I can't find any documentation on it and the data around it is confusing.
>>
>> Does someone have any documentation or examples on how to use the SDK? My
>> project is written in C#, would that be a problem?
>> I understand blender uses OpenCollada. Did the devs have access to some
>> secret documentation or something? :D
>>
>> I've never done something like this before so please assume I'm a total
>> noob.
>>
>> --
>> khalibloo®
>>
>>
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>>
>
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-- 
khalibloo®
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