Surfaces can be triangulated in ADINA using either an advancing front or a Delaunay surface mesher.

Advancing Front

• A standard 2D advancing front algorithm is applied in parameter space.
• Actual distances are obtained from the surface first fundamental form.
• Sizes are controlled by a quadtree built in parameter space.
• Elements are created considering a minimum quality threshold, which can be repeatedly relaxed if the algorithm does not converge.
• There is no optimization or smoothing applied to the obtained mesh.

Delaunay

• A standard 2D Delaunay insertion algorithm is applied in parameter space.
• Sizes are controlled using interpolation on the current mesh.
• Resulting mesh is optimized and smoothed.

Remarks

• The advancing front surface mesher is fast, robust (in its ability to generate a mesh for a given surface), and it creates high quality meshes.
• The Delaunay mesher is probably more robust (in the rare cases the advancing front mesher fails to produce a mesh) but is, at the time being, slower (see timings below). This is not of high concern since the time required to mesh surfaces still represents a small percentage of the total time to mesh a body.
• The Delaunay methodology is employed mostly for special purposes like quadrilateral meshing, anisotropic meshing, curvature-based refinement, and mesh adaptation.

Timings

It is of interest to compare the speeds of the advancing front and Delaunay meshers, and to have an idea of their generation rates. The following tables give numbers of elements generated, CPU times in seconds, and element generation rates per second on an SGI octane for diverse test cases. Note that, for reference, a Pentium II 350 MHz is about 1.2 times slower than a SGI octane for this type of problems. Each table is preceded by pictures of the resulting surface meshes for both meshers. Please click on thumbnails for larger image.

This is a model with mostly primitive surfaces.

This is a model with lofted surfaces.

Other ADINA Mesh Generation Features: