ADR 0001: Keep MMC independent from ICDD and domain profiles

• Status: accepted
• Date: 2026-08-26

Context

DIN 18290-1 defines the MMC 2.0 ZIP envelope, MultiModel.xml, and LinkModel XML. It states that ISO 21597 was considered and permits ICDD ontologies for RDF/OWL models, but normal MMC 2.0 and the GAEB-based DIN 18290 Parts 2–4 are not ICDD archives.

Decision

openbim-mmc directly uses zip and quick-xml and owns only MMC mechanics. It has no dependency on ICDD, GAEB, or IFC.

DIN 18290 LV, cost, and invoice profiles will depend on this crate and the canonical openbim-gaeb crate. Full model validation may additionally depend on canonical IFC. An MMC↔ICDD conversion layer must be a separate adapter depending on both formats.

No normative DIN PDF or schema is redistributed in crate packages. The public buildingSMART-community/MMC schema repository was inspected as prior art at commit 5b440d3a1c0dd33043589ecb6017e8a790385f7c; it has no repository license and no source was copied or vendored.

Consequences

• Core users do not pay for domain dependencies.
• Cargo feature unification cannot make GAEB/IFC mandatory.
• Each format retains its own archive and vocabulary invariants.
• Domain support remains additive without a dependency cycle.

Verification

scripts/gate.sh checks the no-default-feature build and package contents. scripts/mutation-probes.sh demonstrates that security and conformance tests fail when critical guards are weakened.