Calculates and displays Modal Assurance Criterion (MAC) values between pairs of shapes in two Shape Tables.
Each Shape Table can contain ODS's, FEA Mode Shapes, EMA Mode Shapes, or Engineering Data Shapes.
A MAC value is a quantitative method for comparing two complex shape vectors, {u} and {v}. MAC values range between 0 & 1;
MAC = 1.00 - means the two shapes are co-linear, all components of which lie together on a straight line.
MAC > 0.90 - means the two shapes are partially co-linear.
MAC < 0.90 - means the two shapes are not co-linear.
MAC is calculated between two shapes {u} and {v} with the formula;
|| ||2 - denotes the magnitude squared of the vector.
MAC 3D Bar Chart.
WARNING: Only the shape components with matching shape DOFs in the two Shape Tables are used to calculate MAC values.
Coordinate Modal Assurance Criterion (CoMAC) values can also be calculated and displayed between the shape components (or shape DOFs) of pairs of shapes in two Shape Tables. Each Shape Table can contain ODS's, FEA Mode Shapes, EMA Mode Shapes, or Engineering Data Shapes. CoMAC compares shape components from two rows of the DOFs spreadsheets of two Shape Tables.
CoMAC uses the same formula as MAC, but {X} and {Y} are vectors of data from two rows instead of two columns of the M#s spreadsheets. CoMAC values also range between 0 & 1.
CoMAC = 1.00 - means the shape components of all (or selected) shapes are identical for a pair of DOFs
CoMAC > 0.90 - means the shape components of all (or selected) shapes are similar for a pair of DOFs
CoMAC < 0.90 - means the shape components of all (or selected) shapes are different for a pair of DOFs
The following additional commands are contained in the MAC window.
Copies the MAC window graphics to the Windows Clipboard.
Prints the graphics on the system graphics printer.
Closes the MAC window.
Displays the MAC or CoMAC values in a spreadsheet.
Displays the MAC or CoMAC values in a 3D bar chart.
Click & drag to rotate the 3D Bar Chart.
When checked, the MAC or CoMAC value for one shape pair is displayed on the 3D Bar Chart.
Hover the mouse pointer over a bar to display its value.
When checked, either MAC or CoMAC values are displayed in either a 3D Bar Chart or a spreadsheet.
When this option is enabled, a Show MAC control is added to the Animation Tab in the File | Structure Options box .
If Show MAC is checked, the MAC value between the two shapes is displayed during Comparison animation.