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Vehicles

Vehicle is asset type 1 (DeedNFT.AssetType.Vehicle). A Vehicle deed cannot be subdivided. It can be fractionalized like any deed.

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What a validator reviews off-chain before validating a deed, such as the title, the registration or a VIN check, is up to that validator. The contracts do not check documents. They check that the traits below are present, and record the validator's result.

Trait keys

These are the keys the contracts read. Each is a separate trait on the deed, set with DeedNFT.setTrait and a string value (valueType 1). Keys are case-sensitive and hashed with keccak256, so vin and VIN are different traits.

Key
Required by the preset criteria
Used in the metadata name
make
Yes
Yes
model
Yes
Yes
year
Yes
Yes
vin
Yes
No

"Required by the preset criteria" means Validator.setupValidationCriteria(1). A validator can set different criteria with setValidationCriteria (validation-system.md). The preset also requires an operating agreement and a non-empty definition.

The renderer names a Vehicle deed {year} {make} {model}, falling back to {make} {model} and then {make} Vehicle (names).

solidity
deedNFT.setTrait(tokenId, bytes("make"), bytes("Toyota"), 1);
deedNFT.setTrait(tokenId, bytes("model"), bytes("Camry"), 1);
deedNFT.setTrait(tokenId, bytes("year"), bytes("2020"), 1); // a string, not a number
deedNFT.setTrait(tokenId, bytes("vin"), bytes("4T1B11HK0LU000000"), 1);

Every deed also carries the seven traits set at mint: assetType, isValidated, operatingAgreement, definition, configuration, validator and beneficiary.

Other traits and records

Any other string trait is stored and shown in attributes, but no contract reads it. The example metadata in VehicleMetadataTemplate.json suggests labels such as License Plate, Registration State, Color, Body Type, Fuel Type, Transmission, Mileage, Engine Size, Title Number, Title State, Title Status, Registration Expiration, Holding Entity, Condition and Last Service Date.

Supporting records are stored in the MetadataRenderer (stored details):

  • Documents, one URI per type, with manageTokenDocument. The template uses title, registration, service_records, owners_manual and warranty.
  • Legal information with setTokenLegalInfo: jurisdiction, registration number and date, document references, restrictions such as a lien.
  • Condition with setAssetCondition: a general rating, last inspection date, known issues and improvements. Features with setTokenFeatures.

Known limitations

  • year must be a string. Both validateDeed and the renderer decode it as one. Stored as a number (valueType 2), it can make validation revert and the renderer fall back to the stored URI.
  • The example metadata uses display labels, not trait keys. test/templates lists "Make", "Model", "Year" and "VIN". The contracts read make, model, year and vin; a trait set under the label is a different key and is not read.