{
  "schema_version": 1,
  "data_origin_policy": "Analytical and synthetic demonstrations must not be presented as Rheon solver output.",
  "labs": [
    {
      "id": "constant_density_hidden_motion",
      "title": "A bright volume can hide a moving fluid",
      "origin": "analytic prescribed field",
      "controls": [
        "field type",
        "slice position",
        "glyphs",
        "glyph normalization",
        "locked range"
      ],
      "assertions": [
        "constant density/fraction images agree across cases",
        "flux values through unit x-normal face are 0, 1, 0.5 m^3/s",
        "reversing normal reverses flux"
      ],
      "prerequisites": [
        "analytic sampler",
        "slice",
        "glyphs",
        "section integral"
      ],
      "rheon_status": "Can be a teaching fixture independently of solver.",
      "required_visible_metadata": [
        "data origin",
        "field and units",
        "physical time if applicable",
        "range policy",
        "sampling/reconstruction method",
        "invalid-data state"
      ],
      "guide_section": "15, Lab 1"
    },
    {
      "id": "planar_channel",
      "title": "Pressure-driven planar channel",
      "origin": "analytic reference; solver overlay only after qualification",
      "controls": [
        "resolution",
        "pressure gradient",
        "viscosity",
        "slice",
        "profile overlay",
        "pressure gauge shift"
      ],
      "assertions": [
        "Umax/Umean=1.5",
        "flow, pressure drop, wall shear match declared analytical assumptions",
        "gauge shift preserves valid pressure drop"
      ],
      "fixture_key": "planar_channel",
      "prerequisites": [
        "supported viscous/boundary model",
        "field export",
        "native flux",
        "wall derivative if shear is shown"
      ],
      "rheon_status": "Conditional; current SPH box-contact preview is not automatically this model.",
      "required_visible_metadata": [
        "data origin",
        "field and units",
        "physical time if applicable",
        "range policy",
        "sampling/reconstruction method",
        "invalid-data state"
      ],
      "guide_section": "15, Lab 2"
    },
    {
      "id": "gradient_invariants",
      "title": "Vorticity is not a vortex detector",
      "origin": "analytic prescribed field",
      "controls": [
        "rotation/shear/strain/expansion",
        "rate",
        "uniform translation",
        "gradient method",
        "invariant"
      ],
      "assertions": [
        "tensor fixture values match",
        "translation leaves derivatives/invariants unchanged",
        "Q conventions differ for expansion"
      ],
      "fixture_key": "tensor_cases",
      "prerequisites": [
        "sampler",
        "gradient",
        "symmetric eigenvalues"
      ],
      "rheon_status": "Analytic lesson first; branch-specific gradients require validation.",
      "required_visible_metadata": [
        "data origin",
        "field and units",
        "physical time if applicable",
        "range policy",
        "sampling/reconstruction method",
        "invalid-data state"
      ],
      "guide_section": "15, Lab 3"
    },
    {
      "id": "unsteady_curves",
      "title": "Streamline, pathline, and streakline disagree",
      "origin": "analytic time-dependent field",
      "controls": [
        "observation time",
        "release interval",
        "snapshot spacing",
        "integration step",
        "curve type"
      ],
      "assertions": [
        "three curve types agree with formulas",
        "pathline and streakline oldest-particle endpoint is (2,2) at T=2",
        "instantaneous streamline is not relabeled particle history"
      ],
      "fixture_key": "time_dependent_curves",
      "prerequisites": [
        "temporal sampler",
        "integrator",
        "seed/release records"
      ],
      "rheon_status": "Current preview history cannot generate full particle trajectories; use analytic fixture or new quantitative snapshots.",
      "required_visible_metadata": [
        "data origin",
        "field and units",
        "physical time if applicable",
        "range policy",
        "sampling/reconstruction method",
        "invalid-data state"
      ],
      "guide_section": "15, Lab 4"
    },
    {
      "id": "honest_color_range",
      "title": "The color legend can conceal a tenfold change",
      "origin": "synthetic scalar field",
      "controls": [
        "amplitude",
        "autoscale/locked range",
        "probe x",
        "invalid region",
        "out-of-range region"
      ],
      "assertions": [
        "probe at x=.5 changes .5 to 5",
        "locked legend reveals amplitude change",
        "invalid data differs from zero/endpoint"
      ],
      "prerequisites": [
        "legend",
        "scalar map",
        "probe"
      ],
      "rheon_status": "Can ship as teaching lesson with no solver claim.",
      "required_visible_metadata": [
        "data origin",
        "field and units",
        "physical time if applicable",
        "range policy",
        "sampling/reconstruction method",
        "invalid-data state"
      ],
      "guide_section": "15, Lab 5"
    },
    {
      "id": "manufactured_convergence",
      "title": "Does the analysis converge, or only look smoother?",
      "origin": "synthetic convergence sequence",
      "controls": [
        "higher-order error",
        "constant model bias",
        "small perturbation",
        "nonmonotone sequence",
        "display interpolation"
      ],
      "assertions": [
        "observed order=2",
        "extrapolated=1",
        "fine GCI about .968992248 percent",
        "model bias persists under refinement"
      ],
      "fixture_key": "convergence",
      "prerequisites": [
        "chart",
        "formula display",
        "guarded convergence calculator"
      ],
      "rheon_status": "Not evidence about actual Rheon errors.",
      "required_visible_metadata": [
        "data origin",
        "field and units",
        "physical time if applicable",
        "range policy",
        "sampling/reconstruction method",
        "invalid-data state"
      ],
      "guide_section": "15, Lab 6"
    },
    {
      "id": "particle_kernel_coverage",
      "title": "Particle density, coverage, and appearance are different",
      "origin": "synthetic static particle lattice",
      "controls": [
        "probe",
        "kernel support",
        "display resolution",
        "density/normalized attribute",
        "point/voxel/slice view"
      ],
      "assertions": [
        "total mass=125 kg",
        "reference volume=.125 m^3",
        "center density about1009.775167 kg/m^3",
        "outer-face density about816.999908 kg/m^3",
        "normalized attribute does not fix physical support deficiency"
      ],
      "fixture_key": "poly6_lattice",
      "prerequisites": [
        "neighbor search",
        "kernel sampler",
        "support diagnostics",
        "native particle data"
      ],
      "rheon_status": "Directly relevant next lesson; exact solver conventions must be matched before using as Rheon regression.",
      "required_visible_metadata": [
        "data origin",
        "field and units",
        "physical time if applicable",
        "range policy",
        "sampling/reconstruction method",
        "invalid-data state"
      ],
      "guide_section": "15, Lab 7"
    }
  ],
  "implementation_status": "Proposed teaching specifications; no new live browser controls or native solver features are supplied by this file.",
  "source_ledger": "../sources/cad-visualization-sources.json",
  "guide": "../implementation/cad-visualization-contracts.md#seven-interactive-worked-lessons",
  "analytic_generator": "cad_visualization_fixtures.py"
}