.3MF File Format – Production and security

Production extension

Version 1.2. Namespace http://schemas.microsoft.com/3dmanufacturing/production/2015/06 (prefix p); alternatives use http://schemas.microsoft.com/3dmanufacturing/production/alternatives/2021/04 (prefix pa). A package that refers to objects in other model files must list the extension in requiredextensions. UUIDs are any of the RFC 4122 variants, written in the usual 8-4-4-4-12 hexadecimal form.

Objects in other model files

• Only the root model file has a build section, so there is at most one level of referenced files and no cycles.
• A referenced object takes all its resources (materials, textures, thumbnails) from its own file.
• Model-level metadata is read only from the root model file.
• The root model is referenced from /_rels/.rels. The other model files are referenced from the root model’s own relationships part (for /3D/3dmodel.model, /3D/_rels/3dmodel.model.rels) with the 3D model relationship type, never from the package relationships.
• A consumer must report an error if a non-root model file has a component with a path.

Identifiers

The UUIDs are required when the extension is used.

Alternative representations

An object may hold a pa:alternatives element listing other representations of itself, for example a low-resolution preview or an encrypted full model. The consumer picks one it has rights to and whose required extensions it supports; with ties, the first in document order wins. A printer may refuse a lowres model.

<build p:UUID="e9ad5ea8-7e8b-4a5a-9e1b-4f1d2c7a3b10">
  <item objectid="1" p:path="/3D/Objects/part.model"
        p:UUID="0b5c3c34-1f2a-4d65-8a6e-3e3f0a9c4d21"
        transform="1 0 0 0 1 0 0 0 1 20 20 0"/>
</build>

Secure Content extension

Version 1.0.3. Namespace http://schemas.microsoft.com/3dmanufacturing/securecontent/2019/04. Parts are encrypted with a content encryption key (CEK), and each CEK may be wrapped with one or more key encryption keys (KEK), one per authorised consumer. Encrypted parts keep their names and relationships, and are marked with an Encrypted File relationship from the part that refers to them (otherwise from the package). The keys and parameters sit in a key store part, usually /Secure/keystore.xml, referenced from the package relationships with the key store type and, so that editors keep it, a MustPreserve relationship.

Consumers must support RSA-2048 OAEP with MGF1 and SHA-1 or SHA-256. With rsa-oaep-mgf1p the mgfalgorithm must be absent. The key store content type and relationship types are listed on Package and parts.