The Elevate tab provides controls over the target element polynomial degree, smoothing for element curving and quality improvement, and tools for starting and stopping the elevation process.

Grid, Elevate, Elevate Tab
The Elevate tab provides controls for elevating and smoothing high-order volume meshes.

The table at the top of the Elevate tab provides feedback throughout the smoothing phase about the current smoothing pass, current smoothing iteration, number of nodes moved, number of nodes with negative cost (i.e. negative Jacobians), and the minimum curving cost (QMin) value and location. The location of minimum curving cost cell (QMin Location) is also rendered in the Display window as a yellow circle.


Tip: As the elevation process proceeds, the minimum curving cost, Qmin should be positive and the closer it approaches 1 the better. Monitoring QMin with each iteration provides you with feedback on the appropriateness of the inputs set in the Smoothing frame and highlights areas of the mesh where there might be projection or geometry issues.

At the bottom of the Elevate tab are buttons for starting and stopping the elevation process:

  • Elevate/Export: Starts the elevation process. When pressed, the text of the Elevate/Export button changes to Stop. Pressing the Stop button terminates the current elevation without exporting the mesh and returns control to the Elevate task.

Tip: Multiple curved meshes corresponding to different Polynomial Degree and Smoothing settings can be generated by repeated presses of the Elevate / Export button. By default the mesh files will be overwritten, so don't forget to change the export file name on the Export Options tab!

  • Stop Smoothing Pass: Stops the current smoothing pass and either begins the next smoothing pass or, if the target quality has been achieved, exits the WCN smoothing phase and proceeds with CAE export. The Stop Smoothing Pass button is disabled by default and becomes enabled during the WCN smoothing phase.

Polynomial Degree

The Polynomial Degree frame provides options for exporting either a constant order mesh (left), in which all cells are elevated to a uniform polynomial degree (Q2, Q3, or Q4), or a mixed order mesh (right), where the cells are elevated within a polynomial degree range (e.g. Q1-Q4) based on how closely their shape matches the underlying geometry.

The controls in the Polynomial Degree frame allow you to define the target element order in the curved high-order mesh. Mode controls how the cells are elevated and has two options: Constant and Mixed:

  • Constant: specifies that all cells be elevated to a uniform polynomial degree. When selected, a single drop-down menu labeled Degree is provided, allowing you to specify the target uniform element order (Q2, Q3, or Q4). Constant is the default setting for Mode and Q2 is the default setting for Degree.
  • Mixed: specifies that cells be elevated within a range of polynomial degrees based on the deviation between their curved shape and the shape of the underlying geometry. Adjacent elements are allowed to differ by no more than one polynomial degree. The maximum deviation can be specified using the Deviation Threshold control in the Smoothing frame below.

Note: Deviation is also used to ensure conformal matching at interfaces between elements of different orders. In this case, the shape of the lower order element is imposed on the higher order element. Similar conformal matching needs to be done in your CAE solver to ensure that there are no discontinuities at the interface.

When Mixed mode is selected, two drop-down menus are provided for you to specify the desired polynomial degree range for the high-order mesh: Maximum Degree (with options Q2, Q3, and Q4) and Minimum Degree (with options Q1, Q2, Q3, and Q4). Maximum Degree must be set equal or higher than Minimum Degree, otherwise the Elevate / Export button is disabled. The default value for both Maximum Degree and Minimum Degree is taken from the current Degree setting when the mode is switched from Constant.


Caution: Maximum Degree must be set higher than Minimum Degree if you want to elevate a mixed order mesh. If Maximum Degree equals Minimum Degree the elevation process defaults to Constant mode. If Maximum Degree is lower than Minimum Degree the Elevate / Export button is disabled.


The controls in the Smoothing frame allow you to set a desired quality threshold, specify which surface nodes are allowed to move, and improve the stability of the weighted condition number smoothing phase of the high-order elevation process.

The Smoothing frame provides slightly different options for controlling the WCN smoothing based on whether the Mode is set to Constant (left) or Mixed (right).

Convergence Cost Threshold sets a maximum threshold value for the minimum curving cost function. If this maximum is achieved, the WCN smoothing pass stops prior to reaching the specified number of smoothing iterations. Convergence Cost Threshold varies from 0.0 (lowest quality) to 1.0 (highest quality) and defaults to 0.8.

Deviation Threshold sets a maximum threshold for the allowable deviation between the curved mesh shape and the underlying geometry shape for constrained faces and is only available for Mixed mode. Elements exceeding the Deviation Threshold are progressively elevated one order at a time until either the threshold is achieved or the maximum order is reached. The value is scaled relative to the local volume element's minimum linear edge length. Deviation Threshold varies from 0.0 to 1.0 and has a default value of 0.1 (i.e. 10% relative deviation).


Tip: The deviation computation used in the curving phase of the high-order elevation process is similar to that used in the Relative Database Deviation examine metric, except that the value is scaled by the smallest cell edge length instead of the largest. It is a good idea to minimize both the Database Deviation and Relative Database Deviation examine metrics prior to high-order elevation to reduce the total amount of curving required.

Relaxation Factor restricts the step size to be used when iteratively smoothing the high-order nodes in order to maintain stability and varies from 0.0 to 0.5. The default value of 0.05 provides a good mix of robustness and performance. If the WCN smoothing routine is not converging, try reducing the Relaxation Factor.


Tip: If you notice that the WCN smoother is having trouble achieving a positive curving cost (Qmin) or convergence has plateaued, try reducing the Relaxation Factor.

WCN Smoothing Iterations sets the maximum number of iterations for each WCN smoothing pass. WCN Smoothing Iterations is an integer value that ranges from 0 to 10000 and defaults to 100.

Freeze Surface Nodes controls how surface mesh nodes constrained to the geometry are treated during smoothing and has three options: Linear, All, and None. In all cases, the nodes are projected to the geometry prior to smoothing.

  • Linear: Element corner nodes (i.e. the linear, or Q1, nodes) are frozen in place. High-order nodes are free to move. Linear is the default option.
  • All: All element vertices are frozen in place.
  • None: All element vertices are free to move.