[Bf-committers] Help on understanding blender structures

[Brecht Van Lommel]

Hi,

Miguel Torres Lima wrote:
> Hi,
> 
> I'm having some trouble on understanding how the different blender 
> structures are linked. I've been searching the web since morning for 
> some kind of documentation on this subject and didn't find any yet.
> What I really need to know is if a scene structure is directly or 
> indirectly linked to a View3D. If a Scene is indeed a layer, if an 
> Object is an object, what kind of structure is linked to the Object's 
> data field (void *data).

There is high-level documentation on this here:
http://www.blender.org/development/architecture/

It's all explained in the above document, but basically:

- Object.data points to a Mesh, Metaball, .. struct, depending on 
Object.type.
- Object defines among other things the position, rotation, .. .
- Each Scene has a list of Base structs, that each link an Object to 
that Scene.
- Base defines on which layer(s) the Object is in that Scene.

There's no direct link between a 3d view an a Scene. There are always 
exactly 20 layers, and detecting if an object is visible in a 3d view is 
done by doing a bitwise comparison between Base.lay & View3d.lay.

Brecht.