[Bf-committers] GSoC 2009 Proposal Draft: Collada Support Improvements For Blender

[Maxime Curioni]

Hi Chingiz,
Currently using COLLADA as input data format for my own projects and
Illusoft's export script to convert scene, I have a personal interest in
your project and I have a few comments about your proposal.

IMHO, COLLADA DOM is the best option for the project. First, like Ton
mentioned, FCollada's open source version is no longer supported, while
COLLADA DOM is in active development (it supports the latest COLLADA 1.5
release). Second, FCollada is a higher-level solution than COLLADA DOM. You
might consider this a good thing if you are just trying to add COLLADA
support to your program, but if you want to access all the low-level details
yourself, it might not be such an advantage. Since you are writing an
import/export solution, I don't see why you would want such a high-level
access anyway. Finally, I don't think that backward compatibility is a big
problem. The latest 1.5 release already is compatible with the 1.4 spec.
Since the COLLADA specification is becoming stable over time, I think we can
afford to use the latest version of COLLADA DOM.

Besides extending support for animation, I recommend you make your whole
program in C++, that is, you do none of the processing in Python (your
Python scripts should only wrap corresponding C++ functions). Illusoft's
script works well for small scenes but when your mesh data is relatively
large, it takes forever too export. As an example, this week, it took me
more than 3 hours to export an untextured 3d model with 120K faces. I don't
know how Illusoft's script was coded in detail, but I suspect that using
Python to access the mesh data and write to disk is rather inefficient. I am
purely speculating. One thing for sure, it shouldn't take this long and the
user should be provided feedback on the import/export completion.

Best of luck on your project,
Maxime
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