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-   -   Problem importing watertight model into CFX (http://www.cfd-online.com/Forums/ansys/84539-problem-importing-watertight-model-into-cfx.html)

djk1301 February 1, 2011 20:54

Problem importing watertight model into CFX
 
I'm having problems importing a freeform model into CFX. The model is a nurbs based geometry modelled in Rhino. The model is checked for watertightness in rhino. The model is completely closed in rhino and encloses a closed volume. I exported it as IGES to CFX. When I open CFX-pre im getting this message:

CFX-Pre Application Error

ERROR
There was a problem importing the mesh from the requested file.
The importing process reported the following problem:

Model "Model" does not have a valid mesh associated with it.

Body B2997 is an unsuppressed surface body that does not enclose
a volume. Only 3D volume meshes can be imported. If your model
contains valid bodies as well as surface bodies then suppress
the surface bodies and remesh before continuing.

ERROR: Failed to export model.



So the geometry isnt a closed volume anymore. This happened somewhere when importing into CFX or exporting from rhino. Does anyone know how to fix it?

http://dl.dropbox.com/u/3559316/jpgs/3.jpg

http://dl.dropbox.com/u/3559316/jpgs/5.jpg

http://dl.dropbox.com/u/3559316/jpgs/4.jpg





http://dl.dropbox.com/u/3559316/jpgs/3.jpg
http://dl.dropbox.com/u/3559316/jpgs/5.jpg
http://dl.dropbox.com/u/3559316/jpgs/4.jpg

scott February 1, 2011 21:33

Hi Daniel,

You are trying to import a 3D solid body into CFX-Pre, but CFX-Pre is expecting a Mesh file, not a body.

If you are using ANSYS Workbench you will need to import this into Design Modeller, or ANSYS Meshing to then create a mesh that you can import into CFX.

Hope this helps. I presume that you may have some additional issues with your simulation, so can I suggest that you look at the Tutorials and examples included in the Help menu.

Regards,

Scott

djk1301 February 1, 2011 23:00

Scott, thx you for your reply. However i did follow all the workbench steps. I exported from rhino as Iges. Then imported the .iges file in the design modeller. I meshed the geometry in ansys mesher. The problem i get then, that in ansys mesher says the Total volume = 0. If i then go to CFX-pre i get the error that i posted. That has something to do with the fact that my model is not watertight. This lack of watertightness happened somewhere in the export from rhino to IGES or in the import of the .iges file in the design modeller, I think.

scott February 1, 2011 23:04

hmm, for that I am not sure, maybe try to export as Parasolid or Step.

I also have had no luck with Rhino exports in the past (as STL) and have given up!

Design Modeler repair tools might be able to clean up the cad geometry. Use Repair Sliver Surfaces, Repair Spikes, etc etc.

Maybe import only solids, not surfaces and solids to see where any problems are.

Sorry I can't be of more help.

Regards,

Scott


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