[Bf-python] ThinMesh

[joeedh]

Stephen Swaney wrote:

>In another thread Cam Barton wrote:
>
>  
>
>> Keep in mind that some people use Meshes that just
>>about fill there entire system Ram, so making a copy of ALL NMesh data
>>... is not very efficient.
>>    
>>
>
>One of the original bpy design principles was that the bpy interface
>would be thru thin wrappers around Blender data.  'Thin wrappers' means
>that the bpy objects do not make copies of blender data, but instead
>provide a python interface to it.
>
>For most modules this is true, but NMesh is an exception.  It spends a lot
>of time and memory making duplicate copies of existing arrays.  Obviously,
>this is not an efficient use of resources.
>
>Willian and I have discussed the idea of a ThinMesh type that provides
>a true thin wrapper around Blender's Mesh objects.  By accessing 
>blender data directly, we would see big improvements in speed and
>memory consumption when dealing with large meshes.
>
>At one time, this may have been challenging for us, but now that our
>Python extension skills are much improved, maybe it is time to revisit
>this idea.  Anyone looking for a project?
>
>  
>
Main problem: Mesh the structure does everything, and I mean everything, 
in arrays.  So, say to add a vert you have to reallocate the *entire* array.

obviously there are some methods of dealing with this, like leaving room 
for expansion. . .but still, I'm not sure if a thin wrapper would be an 
improvement for Meshes.

Implementation-wise, I would probably write a python list object that 
deals with C arrays and creates wrapper-objects on-the-fly.  Writing it 
in Pyrex might be a good idea, although me personally, I would write the 
module in just normal C.

joeedh