Volume Measurement, Surface Measurement, Line Measurement, Distance Measurement, and Mass Properties
The derived measurement values are used for computing a volume, surface area, or line length for the geometry in a dataset. Also apply an average, maximum (or minimum), or other operation to compute the surface area over the entire dataset for a quantity, for example.
Under Results, right-click Derived Values () or any Evaluation Group node (), and from the Measure submenu select:
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Volume Measurement () to evaluate the volume over a set of domains in 3D models. The result of the evaluation is stored in a Table and displayed in the Table window.
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Surface Measurement () to evaluate a surface area over a set of domains in 2D, 2D axisymmetric, or boundaries in 3D.
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Line Measurement () to evaluate the length of lines over a set of domains in 1D, boundaries in 2D, or edges in 3D.
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 Distance Measurement () to evaluate the distance between two points in the model geometry.
Go to Common Results Node Settings for information about these sections: Data, Selection, and Data Series Operation. For the Distance Measurement, select exactly two points.
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  Mass Properties () to evaluate mass properties: volume, mass, and center of mass. The settings for this node include an Evaluation Settings section, where you select, under Contribution, which mass properties to include and, under Unit, their respective units. You can also select an Integration order checkbox and specify the integration order in the associated text field.
For Mass Properties, only Solution and Mesh datasets based on a 3D component are supported. For Mesh datasets, it is only possible to compute the volume (clear the Mass and Center of mass checkboxes).
Measurement Settings
This section contains settings for the measurement tools:
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From the Unit list, select a compatible unit for the measurement (default SI units: m3 for volumes, m2 for surface areas, and m for lengths of lines and distances).
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If you want to add a custom description, select the Description checkbox and enter a description in the associated text field.
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From the Frame list, select a frame for the measurement. The default is Spatial for a spatial frame. Choose From dataset to use the frame used in the dataset.
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For the Integration order, when available, the COMSOL Multiphysics software determines an appropriate integration order for the expression when you use integration. The default is 4. Select the checkbox to make a different entry in the field (as an integer that is 0 or larger). COMSOL Multiphysics then performs the integration elementwise using numeric quadrature of the selected order.
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For axisymmetric models, the Compute volume of revolved geometry checkbox (for surface measurements) and Compute area of revolved geometry checkbox (for line measurements) are selected by default.