A powerful and important feature of Patran is its geometry capabilities. Geometry can be:

Patran maintains complete accuracy of the original geometry, regardless of where it came from. The exact mathematical representation of the geometry (e.g., Arc, Rational B-Spline, B-rep, Parametric Cubic, etc.) is consistently maintained throughout the modeling process, without any approximations or conversions.

This means different versions of the geometry model are avoided. Only one copy of the geometry design needs to be maintained by the engineer, whether the geometry is in a separate CAD part file or IGES file or the geometry is part of the Patran database.

Below are highlights of the geometry capabilities:

All loads, boundary conditions (BC) and element property assignments can be applied directly to the geometry. When the geometry is meshed with a set of nodes and elements, Patran will automatically assign the loads/BC or element property to the appropriate nodes or elements.

Although you can apply the loads/BCs or element properties directly to the finite element mesh, the advantage of applying them to the geometry is if you remesh the geometry, they remain associated with the model. Once a new mesh is created, the loads/BC and element properties are automatically reassigned.

For more information, see Introduction to Functional Assignment Tasks (Ch. 1) in the Patran Reference Manual.

Direct Geometry Access (DGA) is the capability to directly access (or read) geometry information from an external CAD user file, without the use of an intermediate translator. Currently, DGA supports the following CAD systems:

With DGA, the CAD geometry and its topology that are contained in the CAD user file can be accessed. Once the geometry is accessed, you can build upon or modify the accessed geometry in Patran, mesh the geometry, and assign the loads/BC and the element properties directly to the geometry.

For more detailed information on DGA, see Direct Geometry Access of CAD Geometry, 47.

There are three file formats available to import or export geometry:

In using any of the file formats, Patran maintains the original mathematical form of the geometry. (That is, the geometry is not approximated into the parametric cubic form.) This means the accuracy of the geometry in all three files is maintained.

For more information on the import and export capabilities for IGES, PATRAN 2 Neutral File, and the Express Neutral File, see Accessing, Importing & Exporting Geometry.

You can also create geometry in Patran (“native” geometry). A large number of methods are available to create, translate, and edit geometry, as well as methods to verify, delete and show information.

Patran’s native geometry consists of:

All native geometry is fully parameterized both on the outer boundaries and within the interior (except for B-rep solids which are parameterized only on the outer surfaces).

Fully parameterized geometry means that you can apply varying loads or element properties directly to the geometric entity. Patran evaluates the variation at all exterior and interior locations on the geometric entity.