fem_basis_t4_display, an Octave code which reads data defining a T4 mesh of 4-node triangles, and displays the basis function associated with any node in the mesh.
The entire mesh is shown (which could be a problem for large meshes!). However, a finite element basis function is nonzero over only a relatively small number of elements. Over these elements, the basis function is cubic, and the curved nature of this part of the surface is suggested by taking many plot points in this region.
The best part of the presentation is that MATLAB allows the user to turn the plot or zoom in and out, which makes it much easier to understand the information that is being presented.
The triangular mesh is defined by a node file containing the coordinates of nodes, and an element file containing sets of the four nodes that make up each element.
Note that the four nodes making up each element are to be listed in a particular order, in which the vertices come first, followed by the centroid, as suggested by the following diagram:
3
|\
| \
| \
| \
| 4 \
| \
| \
1-------2
The computer code and data files described and made available on this web page are distributed under the MIT license
fem_basis_t4_display is available in a MATLAB version and an Octave version.
bezier_surface_display, an Octave code which displays a bezier surface.
fem_basis_t3_display, an Octave code which displays a basis function associated with a 3-node t3 mesh.
fem_basis_t6_display, an Octave code which displays a basis function associated with a 6-node t6 mesh.
fem_io, an Octave code which reads and writes the node, element and data files that define a finite element model.
fem2d_pack, an Octave code which is useful for 2d finite element calculations.
fem2d_poisson, an Octave code which solves poisson's equation on a square, using the finite element method.
fem2d_sample, an Octave code which evaluates a finite element function defined on an order 3 or order 6 triangulation.
polygonal_surface_display, an Octave code which reads two files defining a polygonal surface and displays it within MATLAB.
quad_surface_display, an Octave code which reads files defining a 3d quadrilateral mesh surface and displays it within MATLAB.
tet_mesh_display, an Octave code which can read in the node and tetra files defining a tet mesh and display a wireframe image.
tri_surface_display, an Octave code which reads data defining a triangular mesh of a 3d surface and displays it.
triangulation_order6, a directory which contains a description and examples of order 6 triangulations.
triangulation_order6_contour, an Octave code which can make contours of a scalar quantity defined on the nodes of an order 6 triangulation.
triangulation_plot, an Octave code which creates an eps image of a triangulation.