Modelgram

FHIR Logical Model → Diagram

How to use

Modelgram converts FHIR Logical Models (StructureDefinition JSON) into visual diagrams via PlantUML, or exports them to XMI for UML tools like Papyrus or Enterprise Architect.

For background on how these models relate across FHIR, openEHR, UML/XMI and ISO 11179, see the Standards Crosswalk.

Quick start

  1. Paste a URL to a FHIR Logical Model JSON file, or paste the JSON directly
  2. Choose a format and options
  3. Click Fetch & Render or Render from JSON

URL parameters

All inputs can be set via URL query string — useful for linking, embedding, or sharing. Parameters can be combined.

ParameterValuesDescription
url any URL URL of a FHIR Logical Model JSON. Auto-fetches and renders. Falls back to a CORS proxy if the source doesn't allow direct fetch.
json URL-encoded JSON Inline JSON model (alternative to url).
format svg (default), png, txt, xmi Output format. SVG/PNG are diagrams via PlantUML; TXT is ASCII art; XMI is UML for import into modeling tools.
xmi ea (default), papyrus XMI flavor. Only used when format=xmi.
iso11179 true (default), false Include ISO 11179-aligned annotations (ObjectClass / DataElement / Value Domain) as comments. See the Standards Crosswalk.
view differential (default), snapshot Show only what the model adds/changes, or the full element set including inherited. In snapshot view, inherited elements are italic and overridden ones are bold.
datatypes true or 1 Include element datatypes in the output (e.g. <<CodeableConcept>>).
denormalize true or 1 Flatten openEHR-style sliced models (items slices with short names) into normal-looking logical elements.
bg hex color (with or without #) Class box background color. Default is ArchiMate Application Layer blue (#B5E8F7).

Example URLs

  • Quick render as SVG
    ?url=https://.../StructureDefinition-MyModel.json
  • Snapshot view with datatypes as PNG
    ?url=...&view=snapshot&datatypes=true&format=png
  • openEHR-style model, denormalized with types
    ?url=https://build.fhir.org/ig/HL7/fhir-symptoms-ig/en/StructureDefinition-openEHR-EHR-CLUSTER.symptom-sign.v2.json&denormalize=true&datatypes=true
  • Export to XMI for Enterprise Architect
    ?url=...&format=xmi&xmi=ea&denormalize=true

Using the XMI output

  • Papyrus: save the file as .uml, copy into your Papyrus project, double-click — accept the prompt to create .di/.notation wrappers. Right-click the model → New Diagram > Class Diagram, drag classes onto the canvas, then right-click → Filters > Show/Hide Contents to reveal attributes.
  • Enterprise Architect: right-click a package in Project Browser → Import/Export > Import Model from XMI. Use xmi=ea flavor for best compatibility.
or paste JSON