Hooking together surfaces to create volume elements

Having created (hopefully) aligned surfaces you should now be able to hook them together.

The volumes

The volumes have already been created, they reside here. Note that these volumes use different surfaces than those that have been created in this documentation. The elements can be viewed in cmgui using the com file view-volume.com. You should see output like the following image:

Creating the volume elements

New basis functions

These new elements will require different basis functions for interpolation. The previous elements were 2d elements, while these are 3d. The basis functions used can be seen in volume.ipbase.

Linking surfaces together

There is no simple way to do this. In the end, I did it by hand, manually entering the node numbers where the input for elements was prompted. You can do this by typing the following into cm:

fem def elem;p;volumes
And this will give you a prompt like the following:
 Element number [    1]: 1
 The number of geometric Xj-coordinates is [3]: 3
 The basis function type for geometric variable 1 is [1]: 2
 The basis function type for geometric variable 2 is [1]: 2
 The basis function type for geometric variable 3 is [1]: 2
 Enter the 6 global numbers for basis 2: 1 8 14 51 58 64
 Enter the 6 numbers for basis 3 [prev]: 1 8 14 51 58 64
Note:How many nodes you are prompted for is dependent on the basis function entered. Basis function 1 prompts for 8 nodes (ie is a rectangular prism) while basis function 2 prompts for 6 nodes (is a sector element). These sector elements are used at the apex of the heart to close the surface.

Quality

The quality of this final mesh is rather low. Some of the surfaces intersect with each other, and also some of the elements have a certain degree of shear to them.