Peter Alfeld Department of Mathematics College of Science University of Utah
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Designing Finite Elements

To design triangular finite elements click on the red button labeled fin. El. next to the triangulation menu or choose finite elements on that menu.

A control panel will pop up. It lets you choose m which is the number of interior edges attached to each vertex of the macro triangle. m=2k if m is even, and m = 2k-1 if m is odd. You can increment m in steps of 1, or k in steps of 1, which means incrementing m in steps of 2. As you change m and k the split of the macrotriangle changes accordingly. Choose d and r suitably using the control panel or the drawing window.

To impose supersmoothness conditions press SUPER or SPECIAL on the finite element control panel. Additional rows will appear on that panel. They can be used to impose supersmoothness conditions in appropriate groups, to save time and to make it easier for situations where m, d, and r are large. Whether your press SUPER or SPECIAL affects whether in the drawing window you can impose ordinary vertex and edge superspline conditions, or special conditions as described in the User's Guide. In either case, in the finite element control panel you can impose both kinds of conditions.

The colors of the textfields indicate the kind of superspline conditions that can be imposed, as follows:

The best way to familiarize yourself with the controls is probably to click on them and see what they do. However, here is a description:

To exit the setup mode exit Superspline mode as usual or click on Super in the finite element control panel.

Once everything is set up, clicking on the "set It" button will add points the MDS that correspond to the usual boundary data on a finite element.

The "Try again" button reenters superspline mode and lets you modify the supersmoothness conditions.