**Blender files have to follow a set of rules:**

Each article has to be available as Blender Collection.

Each node name has to consist of a->z, A->Z, 0->9 and _

Blender Collections can contain a Sub Collection with a name containing the substring DUPLICATES
These are not exported and shall contain copied meshes for Blender reasons like Armrest_L.001 
The Original Geometry e.g. Armrest_L has to be available outside DUPLICATES collections (see example).

Note: "." as part of a nodename may only appear inside DUPLICATES collections (and therefore never exported)
Note: Collections whose name starts with "_" are ignored and not exported. Tests or helpers can be added this way. 

Geometry normalmaps should be attached to a material attached to a Blendermesh.
Shared Geometry normalmaps should be attached to a single material that is applied to the respective meshes.

If the creation of additional Meshes is contracted, they can live on the root level of the blend.