Quilting for Easier Meshing!

4 Sep 2022 • 2 minute read

While using Fidelity Pointwise, there are two approaches to handling dirty and complex geometries. The first approach is fault tolerant meshing, while the second newer approach is solid meshing. The latter new technique creates models and quilts while importing CAD data into Fidelity Pointwise meshing software.

What are ‘models’ in meshing?

A model is a watertight representation of the geometry. It is just another entity that shows how surfaces relate to one another. In other words, geometry is just a collection of surfaces independent of one another. A model identifies how the surfaces fit together to make a watertight geometry.

What are ‘quilts’ in meshing?

Quilts are the regions within the model that hide unnecessary complex topology in the underlying geometry by identifying meshing region boundaries. Initially, each CAD surface is associated with a single quilt. As long as the quilts are in the same model, they can be joined into larger meshing regions.

Benefits of Quilting

Quilting reduces the surface mesh complexity and prevents skewed CAD surface topology from degrading grid quality.
One domain per quilt is beneficial because it gives users the ability to define regions that reflect the original engineering intent without destroying the watertight nature of the model.
Fewer meshing regions not only simplify the working model but are also more amenable to scripting. Quilts can be identified and named in Fidelity Pointwise, allowing them to be directly called from within a Glyph script.

Applications of Quilting

Hundreds of surfaces defining the aircraft wing geometry in Figure 1. are represented using only a handful of quilts. This reduces the number of database entities one would have to manage while recovering the engineering intent. And if the quilts belong to the same solid model, the resulting surface mesh will be watertight.

Figure 1. 1400 surfaces that make up the wing (left) is represented using only 6 quilts (right) that fully define the meshing regions of the aircraft wing model.

Another application that relies heavily on quilting is the Generic Conventional Model (GCM) semi-truck and trailer shown in Figure 2. By joining quilts into larger regions that represent the physical geometry, the number of quilts was considerably reduced. Quilts on rounds near the trailer floor and roof, as well as the trailer tires, were joined with adjacent quilts. Since these features are small, removing them would not affect the solution significantly.