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Represents a set of properties with some kind of relationship. A 'blockdata' field can copy itself, to duplicate and create several sets. It can contain the following fields: <value>, <container>, <condition>, <function>, <dependencies>, and other <blockdata>
n - Name used to reference the field, especially when writing the .dat file.
There is a special blockdata name n='material' that has an extra meaning to declare that represents a material for import/export materials
Note: all materials of a parent container must have the same fields (value nodes), if there are materials with different properties then must create a container by each type (or define all with the same value nodes some of them unused can have state='hidden')
name - Label that will be visualized by the user. It can be translated.
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