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COBie.Component.Length -- Expected Values

The COBie.Component.Length parameter represents the measured linear length of a component, where applicable.\ This value is used for assets where length is relevant for installation, maintenance, procurement, or asset management. Typical examples include:

  • Pipes\
  • Ducts\
  • Cable trays and conduits\
  • Linear lighting fixtures\
  • Beams and structural members\
  • Expansion joints\
  • Linear mechanical or electrical components

Not all components require a length value. Only components defined in the Responsibility Matrix as length-relevant shall populate this parameter.

Validation Rules (DAQS)

  1. Mandatory for linear assets\ Components with a physical, measurable length (e.g., piping, ducts, cable trays) must provide a Length value.

  2. Numeric format only\ The value shall consist of numeric characters only.

    • Decimal separator: .\
    • No units included in the value\
    • Unit is defined by the project standard (typically millimetres or metres)

    Valid examples:

    • 1200.0\
    • 450\
    • 32.75

  3. No text or symbols\ The following are not permitted:

    • 1200 mm\
    • approx 30\
    • N/A, TBD, --\
    • 1,200 (comma as thousands separator)

  4. Consistency with model geometry\ The Length value shall correspond exactly to the component's modelled geometry.

  5. No zero or negative values\ Length shall be a positive number greater than zero unless explicitly defined otherwise in the BEP.

  6. Responsibility\ The modelling discipline responsible for the asset shall ensure that:

    • The component is modelled to scale\
    • The length parameter is populated correctly\
    • No manual overrides introduce incorrect values

Good Examples

Component Type Valid COBie.Component.Length

Pipe segment 2400 Rectangular duct 1350.5 Cable tray 800 Linear light 1150

Common Mistakes

Incorrect Value Issue

2400 mm Contains units; not allowed 2.400 Thousands format; invalid TBD Placeholder; not permitted 0 Invalid length unless approved by BEP Empty Missing required value for linear components

Relationship to Revit

Autodesk's COBie Extension typically maps this field from:\ Revit → Instance Parameter "Length"\ or a discipline-specific shared parameter, depending on the element category.

Important notes: - Only instance parameters are exported for Component.Length.\ - The Revit model must be correctly constrained and dimensionally accurate.\ - For MEP elements, length is often automatically calculated by Revit, but must still be verified.

Best Practices

  • Ensure all linear components are modelled with correct connectors, geometry, and constraints.\
  • Use Revit schedules to validate lengths before COBie export.\
  • Maintain units consistently in the project (e.g., all lengths expressed in mm).\
  • Avoid overriding length with text-based or user-entered values.\
  • Use DAQS automated validation to flag invalid, missing, or incorrectly formatted length values.