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Description

Attributes define properties or characteristics of system elements, specifying quantitative or qualitative aspects such as dimensions, weight, material properties, performance metrics, or other parameters. In SysML v2, attributes are fundamental modeling elements that capture the values and properties that describe system components. Attributes can contain singular values (strings, numbers, or booleans), or they can reference other attributes in the model, creating calculated relationships between system properties. They support units of measurement and type specifications, enabling precise engineering analysis and ensuring consistency across the model. When attributes reference other values, they can perform unit conversions automatically, allowing engineers to view the same property in different unit systems.
The unit field is optional but recommended for engineering values. When specified, it enables automatic unit conversion and helps prevent errors in calculations. For attributes that reference other attributes, the unit can be changed and the evaluated value will be transformed automatically if the conversion is possible.

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Unit Conversion and Validation

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Automatic Unit Conversion

When an attribute references another attribute with a different unit, Davinci automatically converts between compatible units. This allows you to work with the same physical quantity in different unit systems without manual conversion. Example: If an attribute Length_m has a value of 10 m and another attribute Length_ft references it with units specified as ft, Davinci automatically converts and displays 32.8084 ft. The system supports conversions between:
  • Length units: meters, feet, inches, kilometers, miles, etc.
  • Mass units: kilograms, pounds, grams, tonnes, etc.
  • Time units: seconds, minutes, hours, days, etc.
  • Temperature units: Celsius, Fahrenheit, Kelvin
  • And many more: pressure, velocity, energy, power, etc.
Unit conversion works in equations as well. You can mix units freely in expressions, and Davinci will convert all terms to compatible units before performing calculations.

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Unit Validation

The system validates unit compatibility during equation evaluation to prevent physically meaningless operations. When units are incompatible, Davinci displays an error indicator. Invalid operations that trigger errors:
  • Adding or subtracting incompatible units: 5 m + 3 kg (length + mass)
  • Comparing incompatible quantities: 10 s > 20 m (time > length)
  • Assigning incompatible units: Setting @Length to 25 kg when Length has units of m
Error indicators:
  • Red error box appears next to the attribute value field
  • Hover over the error to see detailed explanation
  • Error message specifies which units are incompatible
The validation system ensures that your model maintains physical consistency and helps catch errors early in the design process.
For custom unit definitions and unit system management, see Unit Settings.

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View Types

ViewDescription
PropertiesEdit the object’s properties, attributes, and metadata.
TableDisplay the object and its children in a tabular format.
RollupVisualize the calculation tree for equation attributes.
RelationshipsExplore the network of connections to other objects.
HistoryTrack changes and revisions to the object.

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Properties Fields

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Name
string
Name of the object.
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Short Name
string
Short name of the object.
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Documentation
string
Description of the object.
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Value
string
The value of the attribute which as the form of:Equation or value [unit] (type)
If the units of the equation or reference either do not match or can not be convereted, an error will occur. Mouseover the error box to see the details of the error.
See the allowed mathmatical operations/syntax and base units for details on what is allowed.
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Relationships
connection
A list of all Relationships this object has with other model objects.Read more about Relationships