CATIA V5 Tutorial: What Is Difference Between Geometrical Set and Ordered Geometrical Set

In Generative Shape Design (GSD) Workbench of CATIA V5, you can find two methods of modeling. These are modeling using ‘Geometrical Sets’ and modeling using ‘Ordered Geometrical Sets’. Both are quite different in approach. In this article we will show you the difference between them.

Module: Generative Shape Design (GSD)
Level: Intermediate

Simple Example to show difference between ‘Geometrical Set’ and ‘Ordered Geometrical Set’

In a new Part, create a Geometrical Set by performing Insert –> Geometrical Set…

Make a Simple Extrude based on a Sketch in XY Plane.

Split the Extrude Surface by using YZ Plane

Here is the resulting Split Surface.

Now CATIA in Geometrical Set mode will let you reuse the “Extrude.1” surface (see below screenshot) even though you have already split it. For example you can create an Offset of the Extrude.

Look at the Parents and Children relationship.

Now consider the same scenario using Ordered Geometrical Set (OGS) mode.
Create a OGS in a Part by performing Insert—>  Ordered Geometrical Set…

Construct the same Sketch, Extrude and Split as done earlier in Geometrical Set mode. Try to Offset the Extrude surface. CATIA will not allow reusing the Extrude because it’s already absorbed by the Split.

Click on image to enlarge
You can only Offset “Split.2” because it is the last operation on the extruded surface.

Summarizing, in Ordered Geometrical Sets, you can’t reuse a absorbed element. Hence modeling is more logical and clean. Wrong methodology of modeling in Geometrical Set usually causes Cross linking problem. Using OGS method, this problem can be avoided.