CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Design modeller ease to use (http://www.cfd-online.com/Forums/cfx/87827-design-modeller-ease-use.html)

taw April 29, 2011 23:27

Design modeller ease to use
 
Sorry, but am I correct to suggest that design modeller (DM) in AWB has limited capability in manipulating some features of solid geometries. For instance I imported a 3D geomety created in solid works (SW), as a parasolid. Yet I wanted to add more sketches by projecting (tracing) from the imported geoemtry. But it doesnot allow me to pick / access the points and edges created in the SW features. There is a command in DM under the "concept" menu "create edges from solid", but this still creates thick edges that are are inacessible to pick/select and trace sketches.

Second, when I do extrude solid bodies for two differnt sketches which are adjecent to eachother, the solid bodies merge. In SW there is an option to overide merging, but I couldnot find such a feature in DM.

So in a nutshell if such simple operations are not supported, it is beater to avoid using DM for creating geometries, esp. for those imported ones. Or it is better to use DM for some unique pre meshing applications like cleaning, simplifying, etc. that would be required for some imported geometries.

Please advise or am I missing a lot of insight on DM. Are there some work arounds to overcome such difficulties.

By the way I choose to to stick with DM for modifying geometries, so that any future geometric modifications on my basic model would be transferred smoothly (seamlessly) to downstream operations, like meshing, cfx-pre, etc.; unlike modifying the original (imported) geometries. Mixing the two approaches seems to stuff up the whole undertaking, which is the position where I am now at.

cheers,

TAW

ghorrocks April 30, 2011 07:55

If you want access to the geometry features you need to use a direct CAD access. If you import a parasolid all the underlying geometry generation is lost and it is just a solid. This is not a failing of DM, just what happens when you import a parasolid. All solid modelling packages would loose the underlying geometry definition when you import parasolids.

Your question about merging bodies shows you missed the basic concept of freezing and unfreezing bodies in DM. Do the tutorials on freezing and unfreezing.

In general I do solid modelling in Solidworks, geometry simplification and other operations to make it suitable for meshing in DM (eg slicing).

taw April 30, 2011 12:16

Dear Ghorrocks,
Thanks for the usual support. I think as you said I should pursue direct CAD approach, since I read such an approach has bidirectional association on the geometry as well as the meshing. This was exactly what I was looking for.

I checked my SW which is 2009/2010 version, has plugin for ANSYS12, which can be actiavted. But I use ANSYS13 and do the latest SW versions has plugins for ANSYS13.

On the extruding command, you are correct I need to do some tut.

Thanks again.

TAW

stumpy May 2, 2011 10:02

The direct CAD connection still won't provide access to the sketches you created in SW.
In DM create a plane where you want the sketch, select the edges, then insert a "Sketch Projection". Other sketches inserted on the same plane can use the lines in the sketch projection.

taw May 2, 2011 16:51

Hi stumpy,

You just gave me an extra ordinary info (http://www.cfd-online.com/Forums/ima...ons/icon14.gif), which I have been bothered about for a while to solve my problem. With freeze/unfreez and sketch projection commands I can now insert or add extra features and manipulations to the basic imported geometry (even with out the need to go to SW now and then). Which I suspect the latter can degenerate some downstream Ansys operations that were completed before the latest modification. For instance I created new faces, from a previous face, for which SW donot support such feattures, and which eventually will be lost when going back to SW for any other changes.


Now I am worried, but not as such stuck with the idea, since I thought that too much manipualtion on the DM will require a lot of (boolean) operations, as I have now witnessed on the pre-meshing and reading geometries (and the like) operations have some how become lengthy, which are understandable. I have my finger crossed the actual solve problem will not be slowed as such.

Thanks any way.

TAW


All times are GMT -4. The time now is 14:23.