# QIF inspection data

Exchanging linked product, inspection-plan and measurement-result information with explicit QIF versions and semantic checks.

Reviewed: 2026-11-01

Tags: parts-and-design, file-formats, inspection

QIF links product definitions to quality information such as measurement plans and results. Verify the identity of the characteristic, the unit and the link to the correct result. [DMSC, QIF overview](https://qifstandards.org/overview/)

In the cited QIF3 schema, the required `versionQIF` attribute is fixed to `3.0.0`, and examples use the namespace `http://qifstandards.org/xsd/qif3`. The required `QPId` is a UUID identifying the document for references from other documents. The required `idMax` describes the largest object identifier used within it. Preserve these identities and references; filenames do not replace them. [QIFDocumentType](https://qualityinformationframework.github.io/qif3-browser/QIFDocument_xsd_Complex_Type_QIFDocumentType.html)

The QIF3 schema makes sections such as Product, Features, Characteristics, Plan, Results, MeasurementResources, Rules and Statistics optional. A file need not contain every area; agree the required exchange content. [QIF3 schema browser, QIFDocumentType](https://qualityinformationframework.github.io/qif3-browser/QIFDocument_xsd_Complex_Type_QIFDocumentType.html)

This reference uses **QIF 3.0 / ISO 23952:2020** as its explicit technical baseline. ISO's public listing identifies edition 1, July 2020, confirmed in 2026. It describes XML instance documents supporting model-based manufacturing quality workflows and the organization of the information model. DMSC identifies the corresponding ANSI release as QIF 3.0-2018. Do not confuse the schema version, standard publication year, document revision and software version. [ISO 23952:2020](https://www.iso.org/standard/77461.html), [DMSC overview](https://qifstandards.org/overview/)

## What information belongs together

QIF's application areas cover different questions:

| Area | Question the exchange should answer |
| --- | --- |
| Model-based definition (MBD) | What product/features and requirements are being inspected? |
| Plans | What measurements are intended? |
| Resources and Rules | What resources or planning rules are described? |
| Results | What measurement information was produced? |
| Statistics | What statistical plans or study results are represented? |

A measurement plan is not automatically an executable program for a particular coordinate measuring machine. Machine execution also needs compatible software, supported operations, equipment configuration and an approved operational workflow. Likewise, displaying PMI does not demonstrate that the receiving application can interpret and use every tolerance semantically.

## Version and identity are explicit

Version changes can affect vocabulary and structure. T. Kramer's **8 March 2019** change guide records, for example, the QIF2.1 names `MeasurementPlan` and `MeasurementsResults` becoming `Plan` and `Results` in QIF3.0, alongside updated keys/keyrefs. Renaming the file extension or changing a version marker does not convert an older payload into the new model. [Changes from QIF 2.1 to QIF 3.0](https://qualityinformationframework.github.io/QIF3.0ChangesFrom2.1.pdf)

DMSC also publishes QIF4.0 development information. Its page's status narrative is explicitly dated June 2023; that narrative should not be treated as a current release announcement. Confirm the actual schema package and supported version with both applications. The examples here remain bounded to the published QIF3 schema. [DMSC, QIF 4.0 development information](https://qifstandards.org/qif-4-0-by-digital-metrology-standards-consortium/)

## Units, datums and result meaning

The document model provides FileUnits, coordinate systems, transforms and datum-reference information. Those fields matter when associating nominal product requirements with measurements. Do not flatten a result into a bare number while discarding its unit, feature association, part identity or coordinate context. [QIFDocumentType](https://qualityinformationframework.github.io/qif3-browser/QIFDocument_xsd_Complex_Type_QIFDocumentType.html)

Agree what a result represents: a reported size, fitted feature parameter, geometric error, raw observation or other measurement quantity. These are not interchangeable. A coordinate reported in one frame cannot be compared directly with one in another frame simply because both use millimeters. A computed acceptance state also depends on the correct requirement and agreed decision rule.

**Original arithmetic example, not QIF XML:** assume characteristic C17 is a bore diameter with nominal 10.000 mm and explicit limits 9.990–10.010 mm. A reported value of 10.006 mm has deviation `10.006 − 10.000 = +0.006 mm` and lies 0.004 mm below the upper limit. This is only a numerical limit comparison. It does not determine conformance when the applicable decision rule includes measurement uncertainty, and it does not establish valid feature association, datum interpretation or measurement method.

For the exchange, retain which physical part and revision C17 belongs to, which measurement event produced the value, its units and the method/resource context required by the recipient. Do not assume that a matching label such as “Diameter 1” uniquely identifies the same feature in two independently revised documents.

## Validation has several levels

The QIF community provides separate schema-validation and XSLT-checking tools. Its validation repository labels additional QIF3plus checks as preview enhancements containing the QIF3 checks plus further checks. Record the tool/check-set version when reporting validation; passing one checker is not a claim that every possible QIF rule or recipient requirement was assessed. [QIF community validation tools](https://github.com/QualityInformationFramework/qif-validation-tools)

The project's check descriptions explain concrete checks for list counts matching `n`, object identifiers not exceeding `idMax`, and external references resolving to the expected URI, document QPId and object. They also describe cross-file type checks, such as ensuring that a circle measurement refers to a circle feature item. Some additional checks are explicitly proposed for future versions; distinguish those from baseline requirements. [QIF3plus Preview, CheckDescriptions](https://github.com/QualityInformationFramework/qif-validation-tools/blob/master/Check%20QIF3plus%20Preview/CheckDescriptions.md)

A sensible receiving sequence is:

1. Parse XML and validate against the agreed schema package/version.
2. Run the applicable additional consistency checks and resolve referenced documents.
3. Confirm product revision, physical-part identity, units, features and characteristics.
4. Compare a representative plan/result set in the receiving application with the source.
5. Apply the agreed inspection and acceptance workflow to the imported information.

A syntactically valid file can still represent the wrong revision or omit information the contract requires. Missing results must not silently become zero measurements or passing outcomes. A successful import can also expose only the subset supported by the application; check that subset against the delivery requirement.

## Handoff requirements and practical limits

Provide the source product revision, QIF/schema version, generating application/version and the intended use: planning, results ingestion, visualization or statistical analysis. State which sections and supporting files are required and how externally linked documents will remain available. Keep the source relationships when storing a results file separately from its nominal definition or plan.

Before relying on automation, demonstrate that the recipient preserves characteristic identity and meaning through a representative export/import cycle. Include cases that matter to the product, such as multiple measurement events, repeated features or referenced documents. QIF supplies a common information model; it does not certify the measurement equipment, validate a sampling strategy, supply absent uncertainty evidence or approve a part for shipment.

## Source versions

The ISO listing identifies July 2020 edition 1 and 2026 confirmation. The QIF3 browser exposes fixed version 3.0.0; it is generated schema documentation rather than a new release date. Kramer's change PDF prints 2019Mar8. DMSC's QIF4.0 status text says June 2023. The cited community pages and validation README do not state a numbered software release; copyright dates are not treated as release dates.

## Related reference

[Drawing and model file references](index.md)