[Bf-python] Fwd: Re: 'obj.data' returns NMesh data object even when made with Mesh class.

[Dietrich Bollmann]

On Wed, 2007-08-08 at 18:49 +1000, Campbell Barton wrote:
> > Is everything in the current API already working in the new 
> > development API?  Would it be wiser to continue working with the 
> > latter one?
> Nope, though Id say its somewhere between 40 and 70% done, but not ready 
> for using.

Ok - I'll wait.

> > How about also implementing a widgets library so that Blender
> > could be used not only as the GUI based 3D/animation editing tool
> > it is now but also as a 3D/animation python extension with GUI 
> > and everything :)  But I think I read this already somewhere
> > in a document about Blenders future?
> 
> leaving this open right now since a user interface and event system 
> update is planned for blender, once thats done were in a better position 
> to plan a new UI module.

Interesting.  By the way - as I found your name beside my "Blender
Command Port" patch (which is rather huge and probably with a lot of
unwanted stuff in it also): In this patch I added some code to the
blender queue to make it thread save.  

I remember reading somewhere that this is not very much appreciated -
but after looking at Blenders event loop I decided that this would make
things a lot clearer than they are for the moment.  And as I wrote
everything for myself in the beginning I didn't mind too much...

> > Another thing I would like to have is a method to dump
> > Objects / datablocks into some textual form which could be 
> > saved in files or a data bank or used to send objects over 
> > a socket.  But probably something like this exist already 
> > and I just don't know about it?
> Your really better off writing this as a python function, and hiding it 
> away in a module you can import, theres so much data you COULD write and 
> you useually dont want to write it all, especially as a text file.

That's what I actually did :)

I initially tried to do this as "Mix-in" - a method to add 
functionality to a class at runtime.  But this doesn't work for 
the moment.  Do you know if "Mix-ins" will work for the 
new API?

Example:

  >>> class A: amember = 111 
  >>> class B: pass 
  >>> b = B() 

The following currently can't work:

  >>> b.amember 
  Traceback (most recent call last): 
    File "<stdin>", line 1, in ? 
  AttributeError: B instance has no attribute 'amember' 

...but in (the current version of) Python works after "mixing" 
class A into the base classes of B:

  >>> B.__bases__ += (A,) 
  >>> b.amember 
  111

Here a posting where I explained my problems with mix-ins
a little better:
http://www.blender.org/forum/viewtopic.php?p=62066#62066

See also "Using Mix-ins with Python" by Chuck Esterbrook at
http://www.linuxjournal.com/article/4540 

> However having a function to write a datablock out to an external blend 
> file would be really nice.

Yes :)  --- My personal code is very experimental and probably 
only usable by me.  But who knows... may be this could be good for
something??

Here an example for a camera setting written to a file:

['scene', 'Scene',
 ['objects', ['list',
                ['object', 'Empty.001',
                 ['LocX', 0.0],
                 ['LocY', 0.0],
                 ['LocZ', 0.270000040531],
                 ['RotX', 0.0],
                 ['RotY', -0.0],
                 ['RotZ', 0.0],
                 ['SizeX', 0.300000011921],
                 ['SizeY', 0.300000011921],
                 ['SizeZ', 0.300000011921],
                 ['type', 'Empty'],
                 ['layers', ['list',
                               16]],
                 ['datablock', None],
                 ['parent', 'scene']],
                ['object', 'Camera.001',
                 ['LocX', -0.983299195766],
                 ['LocY', -0.983299195766],
                 ['LocZ', 0.786232173443],
                 ['RotX', 0.0],
                 ['RotY', -0.0],
                 ['RotZ', 0.0],
                 ['SizeX', 0.19290651381],
                 ['SizeY', 0.192906484008],
                 ['SizeZ', 0.192906469107],
                 ['type', 'Camera'],
                 ['track', 'Empty.001'],
                 ['layers', ['list',
                               16]],
                 ['datablock', 'Camera.001'],
                 ['parent', 'scene']]]],
 ['datablocks', ['list',
                   ['camera', 'Camera.001',
                    ['scale', 6.0],
                    ['lens', 35.0],
                    ['dofDist', 0.0],
                    ['type', 'persp'],
                    ['clipStart', 0.10000000149],
                    ['clipEnd', 100.0],
                    ['drawLimits', False],
                    ['drawMist', False],
                    ['drawName', False],
                    ['drawTileSafe', True],
                    ['drawPassepartout', True],
                    ['alpha', 0.20000000298],
                    ['drawSize', 0.5]]]],
 ['currentCamera', 'Camera.001']]

...most other files are _much_ longer of course.

> as far as network sockets stuff goes, have a look into verse, you can 
> compule blender with verse enabled and edit models over the net with 
> others, tried it and it work ;) though I dont think its production ready.

Thank you, I will have a look :)

Sorry for writing such a long mail - but it is sooo nice to chat from 
time to time :)

Thanks, Dietrich