{
  "title": "Inspect the model, understand the representation — Virtual Acoustic Objects",
  "text": "MODAVIS (2026). Inspect the model, understand the representation — Virtual Acoustic Objects. Research notebooks, October 2026 · Wider reading and source audit edition. https://modavis.org/editions/2026-10-reading/vao/model-study/",
  "bibtex": "@misc{modavis_vao_model_study_2026_10_reading,\n  author = {{MODAVIS}},\n  title = {Inspect the model, understand the representation — Virtual Acoustic Objects},\n  year = {2026},\n  month = {10},\n  version = {2026-10-reading},\n  url = {https://modavis.org/editions/2026-10-reading/vao/model-study/},\n  note = {Content SHA-256: cedd07c6390af7a24888c8bf4e9a16c40d55bd89310284477f6e504f63a54c32}\n}",
  "url": "https://modavis.org/editions/2026-10-reading/vao/model-study/",
  "sha256": "cedd07c6390af7a24888c8bf4e9a16c40d55bd89310284477f6e504f63a54c32",
  "edition": "2026-10-reading",
  "date": "2026-10-09",
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Its scale has not been independently calibrated.\"},{\"id\":\"keyboard\",\"label\":\"Visible keyboard\",\"link\":{\"href\":\"/notebooks/standards/cuntz/#cuntz-profiles\",\"label\":\"Understand profiles and capabilities\"},\"normal\":\"0 0.7071 0.7071\",\"orbit\":\"0deg 75deg auto\",\"position\":\"0m 4.76m -0.44m\",\"text\":\"These modeled keys are visible geometry. This preview does not play the instrument, and no key-to-pipe measurement mapping is asserted. A playable package needs additional data and software behavior.\"}],\"attribution\":\"Recording, data curation, VAO production and maintenance: Dominik Ukolov; measurements: Philipp Hosbach; TASTEN and DISKOS coordination: Dr. Heike Fricke; project leadership: Prof. Dr. Josef Focht; restoration: Markus Brosig and Veit Heller; institution: Leipzig University; hosting: Musikinstrumentenmuseum der Universität Leipzig.\",\"byteSize\":18794860,\"cameraOrbit\":\"25deg 75deg auto\",\"caption\":\"Rotate the model to inspect its represented structure. The light preview simplifies the geometry; “More detail” loads the earlier display derivative. Both derive from the released GLB. Neither is a calibrated survey or a reconstruction certified as the instrument’s state in 1610. Keyboard and stop controls are visual geometry here; this viewer does not play the instrument.\",\"id\":\"cuntz-3d\",\"license\":{\"href\":\"https://creativecommons.org/licenses/by-sa/4.0/\",\"label\":\"CC BY-SA 4.0\"},\"poster\":\"/models/cuntz-poster-ea16e9cd1c29263c.webp\",\"posterSha256\":\"ea16e9cd1c29263cf7892384b12f63c78acfb01fe0ca2f1674f8c7454e430f25\",\"preview\":{\"byteSize\":4067764,\"changes\":\"Light preview derived from the web display model: attribute-aware mesh simplification targets 25% of triangles with an error setting of 0.01, UV weights of 0.5 and normal weights of 0.1; seam collapses are permitted, followed by Meshopt quantization and compression. Texture and node identities are retained. These are algorithm settings, not a bound on historical or physical accuracy.\",\"sha256\":\"e4a393742e76bfe97a0ea1c140832e4309100aa74e1ff8f0b94ec7b7c7688d87\",\"src\":\"/models/cuntz-preview-e4a393742e76bfe9.glb\"},\"provenance\":\"Web display derivative: texture resized to at most 2048 pixels and encoded as JPEG (quality 85); duplicate and unused resources removed and identical vertices welded; meshopt compression with quantization. No historical geometry or physical scale was independently validated. Source realization: urn:musixplora:4010243:cuntz-positiv:realization:model-runtime:4010243_segmented_03b2. Source SHA-256: 19527c2188b08d8536f00299a76c0c73490748298e6cb4dfa07d5b1b684793f5. The poster is a rendered view prepared from the same display geometry.\",\"sha256\":\"6f0dd1a5ea58403da979de9b95ce1232aaf38671d1756ad127a404ba4ae91b47\",\"source\":{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},\"src\":\"/models/cuntz-display-6f0dd1a5ea58403d.glb\",\"title\":\"Cuntz positive organ · a model to inspect\",\"type\":\"model\"},{\"id\":\"view-and-evidence\",\"text\":\"What can this view tell us?\",\"type\":\"heading\"},{\"boundary\":\"The displayed model is a derived visualization with an unverified physical scale. Being about the Cuntz organ does not make every visible detail a measured historical fact.\",\"caseLabel\":\"Cuntz\",\"concept\":\"An ontology is an explicit agreement about the kinds of things we describe and the relationships between them. Its first useful distinction here is between an instrument and a representation of it.\",\"evidence\":\"Released record\",\"expanded\":true,\"id\":\"cuntz-identity\",\"scenario\":\"The physical Cuntz positive organ is identified as mXp 4010243. The release also contains a geometric model and audio files. They concern the instrument, but each has its own identity.\",\"sources\":[{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},{\"detail\":\"Identity, state, configuration, evidence, assertions, context and provenance. Teaching examples explain its distinctions without inventing new normative properties.\",\"href\":\"https://doi.org/10.5281/zenodo.22126086\",\"label\":\"MODAVIS Ontology Network 0.1.0\"}],\"steps\":[{\"text\":\"Use the instrument identity for claims about the organ itself. Its record can link to the museum and to documentary evidence.\",\"title\":\"Name the physical subject\"},{\"text\":\"Give a model, a recording and a playable software product separate identities. A relationship such as “represents this instrument” connects them without declaring them the same thing.\",\"title\":\"Name each representation\"},{\"text\":\"Compressing the model changes its digital realization. It does not rebuild the museum instrument. Repairing a physical component is a different event and needs its own evidence.\",\"title\":\"Follow a change\"}],\"takeaway\":\"An identity answers “which thing?”; a representation relationship answers “what is this about?”.\",\"title\":\"Is the 3D model the Cuntz organ?\",\"type\":\"example\",\"visual\":{\"caption\":\"“Represents” connects these identities; high visual fidelity does not make them identical.\",\"layout\":\"compare\",\"nodes\":[{\"detail\":\"The instrument the research concerns.\",\"icon\":\"compass\",\"label\":\"Physical subject\",\"value\":\"Cuntz positive organ\"},{\"detail\":\"A file representing selected visible features.\",\"icon\":\"cube\",\"label\":\"Digital representation\",\"value\":\"The GLB model\"}],\"title\":\"A representation keeps its own identity\"}},{\"boundary\":\"The notebook deliberately provides viewing controls without a physical measurement ruler.\",\"caseLabel\":\"Cuntz\",\"concept\":\"A coordinate frame defines axes, orientation and units. A verified physical scale additionally requires evidence linking those coordinates to the physical object.\",\"evidence\":\"Released record\",\"expanded\":false,\"id\":\"cuntz-coordinates\",\"scenario\":\"The released model declares a right-handed, Y-up frame with metre units, while its purpose limitation says the source scale has not been verified by a physical survey.\",\"sources\":[{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},{\"detail\":\"The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2.\",\"href\":\"https://doi.org/10.5281/zenodo.22214248\",\"label\":\"VAO Standard 0.5.0\"}],\"steps\":[{\"text\":\"The convention tells a renderer how to interpret model coordinates and orient the scene. It helps two applications agree about the same geometry.\",\"title\":\"Read the coordinate convention\"},{\"text\":\"A declared metre unit does not supply a missing calibration. If the original geometry scale was not verified, a distance computed from its vertices must not be advertised as a measured organ dimension.\",\"title\":\"Read the qualification\"},{\"text\":\"For a documented pipe quantity, inspect the identified measurement observation and workbook source. Use the model to locate and discuss shapes within its stated limitations.\",\"title\":\"Use appropriate evidence for dimensions\"}],\"takeaway\":\"Coordinate consistency allows interchange; metrological validity requires additional evidence.\",\"title\":\"Can we measure the original organ by rotating its model?\",\"type\":\"example\",\"visual\":{\"caption\":\"The Cuntz display model has not been independently calibrated for physical measurement.\",\"layout\":\"compare\",\"nodes\":[{\"detail\":\"A viewer can rotate and zoom the representation.\",\"icon\":\"cube\",\"label\":\"Model coordinates\",\"value\":\"Scene geometry\"},{\"detail\":\"Needs a documented unit, frame and calibration.\",\"icon\":\"compass\",\"label\":\"Physical measurement\",\"value\":\"Calibrated dimensions\"}],\"title\":\"A model unit is not automatically a millimetre\"}},{\"id\":\"from-source-to-display\",\"text\":\"How this display differs from the archived file\",\"type\":\"heading\"},{\"boundary\":\"Compression and a rendered appearance do not establish geometric measurement accuracy or recover the object’s original appearance.\",\"caseLabel\":\"Cuntz\",\"concept\":\"Provenance is a trace of inputs, transformations, outputs and responsible agents. PROV-O provides a vocabulary for describing those roles.\",\"evidence\":\"Released record\",\"expanded\":false,\"id\":\"cuntz-provenance\",\"scenario\":\"The published Cuntz release identifies an FBX source model and a derived GLB runtime model. This notebook displays a further web derivative of that released GLB.\",\"sources\":[{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},{\"detail\":\"The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2.\",\"href\":\"https://doi.org/10.5281/zenodo.22214248\",\"label\":\"VAO Standard 0.5.0\"}],\"steps\":[{\"text\":\"Before preparing the web model, compare its source bytes and SHA-256 with the exact published runtime realization. A similar filename is insufficient.\",\"title\":\"Fix the input\"},{\"text\":\"For this website, the texture is resized to at most 2048 pixels and encoded as JPEG. Duplicate and unused resources are removed, and meshopt compression applies quantization. These changes are documented with the derivative.\",\"title\":\"Describe the transformation\"},{\"text\":\"The web file has its own byte size and digest. It remains linked to the source release and source realization, while being described as a display derivative rather than the unmodified archived GLB.\",\"title\":\"Give the output its own identity\"}],\"takeaway\":\"A derivative can be useful and traceable without being byte-identical to its source.\",\"title\":\"How did the model on this page come into being?\",\"type\":\"example\",\"visual\":{\"caption\":\"A smaller display file is a new realization. Derivation does not certify scale or historical accuracy.\",\"layout\":\"flow\",\"nodes\":[{\"detail\":\"115,416,448 bytes, with its released digest.\",\"icon\":\"cube\",\"label\":\"Released realization\",\"value\":\"Source GLB\"},{\"detail\":\"Texture reduction, welding and Meshopt compression.\",\"icon\":\"layers\",\"label\":\"Web display\",\"value\":\"Detailed derivative\"},{\"detail\":\"4,067,764 bytes; original attribution retained.\",\"icon\":\"compass\",\"label\":\"Light preview\",\"value\":\"Simplified derivative\"}],\"relations\":[\"document the conversion\",\"document the simplification\"],\"title\":\"Keep the model’s transformations visible\"}},{\"boundary\":\"This website verifies the model’s expected byte length and full SHA-256 before passing it to the renderer. That is a file-identity check, not a VAO conformance report.\",\"caseLabel\":\"Cuntz\",\"concept\":\"A checksum is a fingerprint calculated from bytes. Fixity checking compares that fingerprint with a trusted expected value to detect changed or mismatched files.\",\"evidence\":\"Released record\",\"expanded\":false,\"id\":\"cuntz-fixity\",\"scenario\":\"The published GLB source for this notebook has SHA-256 beginning 19527c2188b08d85. The display derivative has a different digest because its texture and encoding were changed.\",\"sources\":[{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},{\"detail\":\"The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2.\",\"href\":\"https://doi.org/10.5281/zenodo.22214248\",\"label\":\"VAO Standard 0.5.0\"}],\"steps\":[{\"text\":\"Check the complete source GLB digest against the exact source realization. Compare the website derivative against its own expected digest, not against the source GLB’s digest.\",\"title\":\"Compare like with like\"},{\"text\":\"A texture conversion or mesh encoding change produces a different file identity. Even reformatting a JSON manifest can change its exact-byte hash without changing its parsed meaning.\",\"title\":\"Notice byte-changing edits\"},{\"text\":\"Matching bytes establish which representation was obtained. The digest does not verify the model’s physical scale, the pipe measurement method or a claim about the sound of 1610.\",\"title\":\"Keep the scientific question separate\"}],\"takeaway\":\"Fixity makes evidence identifiable; it does not independently validate the evidence’s interpretation.\",\"title\":\"What does the model’s SHA-256 prove?\",\"type\":\"example\",\"visual\":{\"caption\":\"A digest match establishes exact-byte agreement, not scientific adequacy, authenticity or rights clearance.\",\"layout\":\"flow\",\"nodes\":[{\"detail\":\"Read the exact realization record.\",\"icon\":\"database\",\"label\":\"Expected identity\",\"value\":\"Size + SHA-256\"},{\"detail\":\"Hash the actual bytes you obtained.\",\"icon\":\"compass\",\"label\":\"Acquired file\",\"value\":\"Compute its digest\"},{\"detail\":\"Keep the result and its input identity.\",\"icon\":\"check\",\"label\":\"Comparison\",\"value\":\"Match or mismatch\"}],\"relations\":[\"compare with the download\",\"record the outcome\"],\"title\":\"Compare the bytes with the released expectation\"}},{\"text\":\"The viewer loads only after you select “Explore in 3D”. The expected byte size and SHA-256 are checked before display. Source attribution and download links remain usable without the 3D view; the poster and explanation are included in print. The camera controls affect only your view, not the source geometry.\",\"type\":\"p\"},{\"items\":[{\"detail\":\"Objects, states, observations, evidence and review.\",\"href\":\"/notebooks/ontologies/cuntz/\",\"label\":\"Understand the ontology through Cuntz\"},{\"detail\":\"Assets, realizations, delivery, validation and citation.\",\"href\":\"/notebooks/standards/cuntz/\",\"label\":\"Understand the VAO contract through Cuntz\"}],\"type\":\"links\"}],\"intro\":\"A 3D model is a useful way to examine a representation. The Cuntz example shows why its source, transformations, coordinate conventions and scientific limits belong beside the view.\",\"slug\":\"model-study\",\"sources\":[{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},{\"detail\":\"The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2.\",\"href\":\"https://doi.org/10.5281/zenodo.22214248\",\"label\":\"VAO Standard 0.5.0\"}],\"title\":\"Inspect the model, understand the representation\"},\"date\":\"2026-10-09\",\"edition\":\"2026-10-reading\",\"figures\":{}}",
  "payload": {
    "edition": "2026-10-reading",
    "date": "2026-10-09",
    "book": {
      "slug": "vao",
      "title": "Virtual Acoustic Objects",
      "number": "01"
    },
    "chapter": {
      "slug": "model-study",
      "title": "Inspect the model, understand the representation",
      "intro": "A 3D model is a useful way to examine a representation. The Cuntz example shows why its source, transformations, coordinate conventions and scientific limits belong beside the view.",
      "sources": [
        {
          "label": "Cuntz Positiv · VAO 0.5.0-rc.2",
          "href": "https://doi.org/10.5281/zenodo.22151203",
          "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release."
        },
        {
          "label": "VAO Standard 0.5.0",
          "href": "https://doi.org/10.5281/zenodo.22214248",
          "detail": "The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2."
        }
      ],
      "blocks": [
        {
          "type": "model",
          "id": "cuntz-3d",
          "title": "Cuntz positive organ · a model to inspect",
          "src": "/models/cuntz-display-6f0dd1a5ea58403d.glb",
          "poster": "/models/cuntz-poster-ea16e9cd1c29263c.webp",
          "posterSha256": "ea16e9cd1c29263cf7892384b12f63c78acfb01fe0ca2f1674f8c7454e430f25",
          "alt": "A rendered view of the Cuntz positive organ model, showing its decorated case, open side doors, pipe front and keyboard.",
          "caption": "Rotate the model to inspect its represented structure. The light preview simplifies the geometry; “More detail” loads the earlier display derivative. Both derive from the released GLB. Neither is a calibrated survey or a reconstruction certified as the instrument’s state in 1610. Keyboard and stop controls are visual geometry here; this viewer does not play the instrument.",
          "byteSize": 18794860,
          "sha256": "6f0dd1a5ea58403da979de9b95ce1232aaf38671d1756ad127a404ba4ae91b47",
          "source": {
            "label": "Cuntz Positiv · VAO 0.5.0-rc.2",
            "href": "https://doi.org/10.5281/zenodo.22151203",
            "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release."
          },
          "license": {
            "label": "CC BY-SA 4.0",
            "href": "https://creativecommons.org/licenses/by-sa/4.0/"
          },
          "attribution": "Recording, data curation, VAO production and maintenance: Dominik Ukolov; measurements: Philipp Hosbach; TASTEN and DISKOS coordination: Dr. Heike Fricke; project leadership: Prof. Dr. Josef Focht; restoration: Markus Brosig and Veit Heller; institution: Leipzig University; hosting: Musikinstrumentenmuseum der Universität Leipzig.",
          "provenance": "Web display derivative: texture resized to at most 2048 pixels and encoded as JPEG (quality 85); duplicate and unused resources removed and identical vertices welded; meshopt compression with quantization. No historical geometry or physical scale was independently validated. Source realization: urn:musixplora:4010243:cuntz-positiv:realization:model-runtime:4010243_segmented_03b2. Source SHA-256: 19527c2188b08d8536f00299a76c0c73490748298e6cb4dfa07d5b1b684793f5. The poster is a rendered view prepared from the same display geometry.",
          "cameraOrbit": "25deg 75deg auto",
          "preview": {
            "src": "/models/cuntz-preview-e4a393742e76bfe9.glb",
            "sha256": "e4a393742e76bfe97a0ea1c140832e4309100aa74e1ff8f0b94ec7b7c7688d87",
            "byteSize": 4067764,
            "changes": "Light preview derived from the web display model: attribute-aware mesh simplification targets 25% of triangles with an error setting of 0.01, UV weights of 0.5 and normal weights of 0.1; seam collapses are permitted, followed by Meshopt quantization and compression. Texture and node identities are retained. These are algorithm settings, not a bound on historical or physical accuracy."
          },
          "annotations": [
            {
              "id": "representation",
              "label": "Model and instrument",
              "position": "0m 8m -0.3m",
              "normal": "0 0 1",
              "orbit": "25deg 75deg auto",
              "text": "This geometry represents the Cuntz organ. Rotating or simplifying it changes a digital view or file, not the physical instrument. Its scale has not been independently calibrated.",
              "link": {
                "label": "Understand the identity distinction",
                "href": "#cuntz-identity"
              }
            },
            {
              "id": "keyboard",
              "label": "Visible keyboard",
              "position": "0m 4.76m -0.44m",
              "normal": "0 0.7071 0.7071",
              "orbit": "0deg 75deg auto",
              "text": "These modeled keys are visible geometry. This preview does not play the instrument, and no key-to-pipe measurement mapping is asserted. A playable package needs additional data and software behavior.",
              "link": {
                "label": "Understand profiles and capabilities",
                "href": "/notebooks/standards/cuntz/#cuntz-profiles"
              }
            }
          ]
        },
        {
          "type": "heading",
          "id": "view-and-evidence",
          "text": "What can this view tell us?"
        },
        {
          "type": "example",
          "id": "cuntz-identity",
          "title": "Is the 3D model the Cuntz organ?",
          "concept": "An ontology is an explicit agreement about the kinds of things we describe and the relationships between them. Its first useful distinction here is between an instrument and a representation of it.",
          "scenario": "The physical Cuntz positive organ is identified as mXp 4010243. The release also contains a geometric model and audio files. They concern the instrument, but each has its own identity.",
          "steps": [
            {
              "title": "Name the physical subject",
              "text": "Use the instrument identity for claims about the organ itself. Its record can link to the museum and to documentary evidence."
            },
            {
              "title": "Name each representation",
              "text": "Give a model, a recording and a playable software product separate identities. A relationship such as “represents this instrument” connects them without declaring them the same thing."
            },
            {
              "title": "Follow a change",
              "text": "Compressing the model changes its digital realization. It does not rebuild the museum instrument. Repairing a physical component is a different event and needs its own evidence."
            }
          ],
          "takeaway": "An identity answers “which thing?”; a representation relationship answers “what is this about?”.",
          "boundary": "The displayed model is a derived visualization with an unverified physical scale. Being about the Cuntz organ does not make every visible detail a measured historical fact.",
          "sources": [
            {
              "label": "Cuntz Positiv · VAO 0.5.0-rc.2",
              "href": "https://doi.org/10.5281/zenodo.22151203",
              "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release."
            },
            {
              "label": "MODAVIS Ontology Network 0.1.0",
              "href": "https://doi.org/10.5281/zenodo.22126086",
              "detail": "Identity, state, configuration, evidence, assertions, context and provenance. Teaching examples explain its distinctions without inventing new normative properties."
            }
          ],
          "expanded": true,
          "caseLabel": "Cuntz",
          "evidence": "Released record",
          "visual": {
            "layout": "compare",
            "title": "A representation keeps its own identity",
            "nodes": [
              {
                "label": "Physical subject",
                "value": "Cuntz positive organ",
                "detail": "The instrument the research concerns.",
                "icon": "compass"
              },
              {
                "label": "Digital representation",
                "value": "The GLB model",
                "detail": "A file representing selected visible features.",
                "icon": "cube"
              }
            ],
            "caption": "“Represents” connects these identities; high visual fidelity does not make them identical."
          }
        },
        {
          "type": "example",
          "id": "cuntz-coordinates",
          "title": "Can we measure the original organ by rotating its model?",
          "concept": "A coordinate frame defines axes, orientation and units. A verified physical scale additionally requires evidence linking those coordinates to the physical object.",
          "scenario": "The released model declares a right-handed, Y-up frame with metre units, while its purpose limitation says the source scale has not been verified by a physical survey.",
          "steps": [
            {
              "title": "Read the coordinate convention",
              "text": "The convention tells a renderer how to interpret model coordinates and orient the scene. It helps two applications agree about the same geometry."
            },
            {
              "title": "Read the qualification",
              "text": "A declared metre unit does not supply a missing calibration. If the original geometry scale was not verified, a distance computed from its vertices must not be advertised as a measured organ dimension."
            },
            {
              "title": "Use appropriate evidence for dimensions",
              "text": "For a documented pipe quantity, inspect the identified measurement observation and workbook source. Use the model to locate and discuss shapes within its stated limitations."
            }
          ],
          "takeaway": "Coordinate consistency allows interchange; metrological validity requires additional evidence.",
          "boundary": "The notebook deliberately provides viewing controls without a physical measurement ruler.",
          "sources": [
            {
              "label": "Cuntz Positiv · VAO 0.5.0-rc.2",
              "href": "https://doi.org/10.5281/zenodo.22151203",
              "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release."
            },
            {
              "label": "VAO Standard 0.5.0",
              "href": "https://doi.org/10.5281/zenodo.22214248",
              "detail": "The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2."
            }
          ],
          "expanded": false,
          "caseLabel": "Cuntz",
          "evidence": "Released record",
          "visual": {
            "layout": "compare",
            "title": "A model unit is not automatically a millimetre",
            "nodes": [
              {
                "label": "Model coordinates",
                "value": "Scene geometry",
                "detail": "A viewer can rotate and zoom the representation.",
                "icon": "cube"
              },
              {
                "label": "Physical measurement",
                "value": "Calibrated dimensions",
                "detail": "Needs a documented unit, frame and calibration.",
                "icon": "compass"
              }
            ],
            "caption": "The Cuntz display model has not been independently calibrated for physical measurement."
          }
        },
        {
          "type": "heading",
          "id": "from-source-to-display",
          "text": "How this display differs from the archived file"
        },
        {
          "type": "example",
          "id": "cuntz-provenance",
          "title": "How did the model on this page come into being?",
          "concept": "Provenance is a trace of inputs, transformations, outputs and responsible agents. PROV-O provides a vocabulary for describing those roles.",
          "scenario": "The published Cuntz release identifies an FBX source model and a derived GLB runtime model. This notebook displays a further web derivative of that released GLB.",
          "steps": [
            {
              "title": "Fix the input",
              "text": "Before preparing the web model, compare its source bytes and SHA-256 with the exact published runtime realization. A similar filename is insufficient."
            },
            {
              "title": "Describe the transformation",
              "text": "For this website, the texture is resized to at most 2048 pixels and encoded as JPEG. Duplicate and unused resources are removed, and meshopt compression applies quantization. These changes are documented with the derivative."
            },
            {
              "title": "Give the output its own identity",
              "text": "The web file has its own byte size and digest. It remains linked to the source release and source realization, while being described as a display derivative rather than the unmodified archived GLB."
            }
          ],
          "takeaway": "A derivative can be useful and traceable without being byte-identical to its source.",
          "boundary": "Compression and a rendered appearance do not establish geometric measurement accuracy or recover the object’s original appearance.",
          "sources": [
            {
              "label": "Cuntz Positiv · VAO 0.5.0-rc.2",
              "href": "https://doi.org/10.5281/zenodo.22151203",
              "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release."
            },
            {
              "label": "VAO Standard 0.5.0",
              "href": "https://doi.org/10.5281/zenodo.22214248",
              "detail": "The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2."
            }
          ],
          "expanded": false,
          "caseLabel": "Cuntz",
          "evidence": "Released record",
          "visual": {
            "layout": "flow",
            "title": "Keep the model’s transformations visible",
            "nodes": [
              {
                "label": "Released realization",
                "value": "Source GLB",
                "detail": "115,416,448 bytes, with its released digest.",
                "icon": "cube"
              },
              {
                "label": "Web display",
                "value": "Detailed derivative",
                "detail": "Texture reduction, welding and Meshopt compression.",
                "icon": "layers"
              },
              {
                "label": "Light preview",
                "value": "Simplified derivative",
                "detail": "4,067,764 bytes; original attribution retained.",
                "icon": "compass"
              }
            ],
            "caption": "A smaller display file is a new realization. Derivation does not certify scale or historical accuracy.",
            "relations": [
              "document the conversion",
              "document the simplification"
            ]
          }
        },
        {
          "type": "example",
          "id": "cuntz-fixity",
          "title": "What does the model’s SHA-256 prove?",
          "concept": "A checksum is a fingerprint calculated from bytes. Fixity checking compares that fingerprint with a trusted expected value to detect changed or mismatched files.",
          "scenario": "The published GLB source for this notebook has SHA-256 beginning 19527c2188b08d85. The display derivative has a different digest because its texture and encoding were changed.",
          "steps": [
            {
              "title": "Compare like with like",
              "text": "Check the complete source GLB digest against the exact source realization. Compare the website derivative against its own expected digest, not against the source GLB’s digest."
            },
            {
              "title": "Notice byte-changing edits",
              "text": "A texture conversion or mesh encoding change produces a different file identity. Even reformatting a JSON manifest can change its exact-byte hash without changing its parsed meaning."
            },
            {
              "title": "Keep the scientific question separate",
              "text": "Matching bytes establish which representation was obtained. The digest does not verify the model’s physical scale, the pipe measurement method or a claim about the sound of 1610."
            }
          ],
          "takeaway": "Fixity makes evidence identifiable; it does not independently validate the evidence’s interpretation.",
          "boundary": "This website verifies the model’s expected byte length and full SHA-256 before passing it to the renderer. That is a file-identity check, not a VAO conformance report.",
          "sources": [
            {
              "label": "Cuntz Positiv · VAO 0.5.0-rc.2",
              "href": "https://doi.org/10.5281/zenodo.22151203",
              "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release."
            },
            {
              "label": "VAO Standard 0.5.0",
              "href": "https://doi.org/10.5281/zenodo.22214248",
              "detail": "The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2."
            }
          ],
          "expanded": false,
          "caseLabel": "Cuntz",
          "evidence": "Released record",
          "visual": {
            "layout": "flow",
            "title": "Compare the bytes with the released expectation",
            "nodes": [
              {
                "label": "Expected identity",
                "value": "Size + SHA-256",
                "detail": "Read the exact realization record.",
                "icon": "database"
              },
              {
                "label": "Acquired file",
                "value": "Compute its digest",
                "detail": "Hash the actual bytes you obtained.",
                "icon": "compass"
              },
              {
                "label": "Comparison",
                "value": "Match or mismatch",
                "detail": "Keep the result and its input identity.",
                "icon": "check"
              }
            ],
            "caption": "A digest match establishes exact-byte agreement, not scientific adequacy, authenticity or rights clearance.",
            "relations": [
              "compare with the download",
              "record the outcome"
            ]
          }
        },
        {
          "type": "p",
          "text": "The viewer loads only after you select “Explore in 3D”. The expected byte size and SHA-256 are checked before display. Source attribution and download links remain usable without the 3D view; the poster and explanation are included in print. The camera controls affect only your view, not the source geometry."
        },
        {
          "type": "links",
          "items": [
            {
              "label": "Understand the ontology through Cuntz",
              "href": "/notebooks/ontologies/cuntz/",
              "detail": "Objects, states, observations, evidence and review."
            },
            {
              "label": "Understand the VAO contract through Cuntz",
              "href": "/notebooks/standards/cuntz/",
              "detail": "Assets, realizations, delivery, validation and citation."
            }
          ]
        }
      ]
    },
    "figures": {}
  }
}