In part 1 of this 3-part series, we introduced you to our paper on Preparing Geometry Models for Mesh Generation and CFD. With geometry preparation and mesh generation representing a significant bottleneck in CFD workflows, it’s important for everyone to understand why.

The first major section of the paper provides background on the various methods used to represent not only geometry but topology, the latter being essential in many cases for the modeling of complex shapes such as aircraft, jet engines, and automobiles.

Broadly speaking, there are two categories of solid object representation: boundary representation and volumetric representation.

Boundary representation is the method of describing a solid object implicitly from its boundary and generally consists of two sub-representations: geometry and topology. Geometry is the term used to describe individual shapes such as points, curves, and surfaces, which are typically parametric mappings from a lower-dimensional space into 3D. Topology is the term used to describe the entities that limit the portion of each geometric shape and the interconnections between those limited shapes.

The paper provides background on the various types of geometry including analytic representations such as B-Splines, T-Splines, U-Splines, and subdivision and discrete geometry such as meshes and 3D scans. Topology in the form of trimming the geometry in order to model complex shapes is also introduced. You will likely recognize these methods and terms because they are the primary form of geometry models produced by contemporary mechanical CAD software.

The section on volumetric representations introduces constructive solid geometry (CSG), spatial occupancy techniques, and implicit modeling. The latter is an up-and-coming technique that is very well suited for the complex shapes produced by generative design and topology optimization techniques.

Implicit modeling is well-suited for use with design optimization in which models can be created that might otherwise be impossible or at least impractical to design, particularly in cases where the topology of the overall shape changes drastically.

The paper’s 20 pages include 43 references allowing the interested reader to dig deeper into any of the topics that interests them the most. Go to our website and download Preparation of Geometry Models for Mesh Generation and CFD today.