With the new CAD model import options in CFD-GEOM, it is now easier than ever to read your solid models into CFD-GEOM.  Once the model is in CFD-GEOM, you have the solid representation of the part but in many cases the fluid, or negative space, in the CAD model is of importance and the area which needs to be discretized (i.e. meshed).  In V2008.2, CFD-GEOM can now "invert" these models to give you just the fluid region or the fluid region plus the solid part with a single click.  This new tool is called "Invert Model" and can be found on the Geometry tab under the Solid and Wireframe Tools, as shown in Figure 1.

  Figure 1.  Invert Model tool in CFD-GEOM V2008.2

When doing Model Inversion, there a few things to keep in mind:

• Available for inverting Unstructured Domain(s) not constructed from Edges, Faces, nor Discreet Surfaces
• The domain(s)  must have defined cap-able inlet/outlet holes.
• Except at the caps, the domain(s) must have a finite thickness throughout, i.e. it must be a solid (Unstructured Domain in CFD-GEOM).
• Model inversion is not part of the Undo system, so be sure to save the model before inversion.
• Ideally, inversion should be done immediately after the model has been read into CFD-GEOM. 
  
• Option to discard or keep the original solid.

To perform a Model Inversion, do the following steps:

1. Read the CAD model into CFD-GEOM
2. Identify the cap-able inlet and outlet surfaces in the model
3. Go the the Invert Model tool and select the inlet and outlet surfaces that cap the model.
4. Click the Apply button to invert the model.

Note that as a part of the process, untrimmed surfaces are created when performing a model inversion.  These can be deleted or blanked from the model since they are not needed.  In future versions of CFD-GEOM, these untrimmed surfaces may be deleted as a part of the model inversion tool. 

To view a short movie demonstrating the inversion capability, please click here.  To download the model used in the tip, please click here.

This is one of the many new features in the V2008.2 version of CFD-GEOM.  If you have not already upgraded, we strongly suggest you do so you can use these new features and enhancements.

Regards,
William Kuykendall
ESI CFD Support Team