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-   -   ICEM-CFD - Catia Interface: anybody experienced? (https://www.cfd-online.com/Forums/main/4095-icem-cfd-catia-interface-anybody-experienced.html)

Helge November 20, 2001 12:37

Re: Geometry simplification and repair
 
1) Your shrink wrap seems to be a good solution. I have not tried it out. But what does your skrink wrap do when there is a hole in the surface you like to shrink around ? 2) Concerning the fact that ICEM tetra and Hexa do work patch independent I would say that the approach to keep every detail in the CAD model and then in the tetin file will work up to a certain extend of complexity. If you have hundreds of bolts, ribs etc. it will be hard to navigate through all that in ICEM 3) I would try that way with an air duct but not for a complete motor

Judd Kaiser November 20, 2001 13:10

Re: Geometry simplification and repair
 
In ICEM CFD, the 'shrink wrap' is called 'convex hull'. Think about it as wrapping a blanket around whatever entities you select. It creates an enclosed surface which will be defined by all the boundaries of the entities you select. If there are holes, the shrink wrapped surface will close them.

If you want to capture certain features when performing the convex hull, you can optionally define 'split planes'. You might think about these split planes as locations where you want to 'pull the blanket tight'.

Also keep in mind that some of the CAD tools have good shrink wrap tools built in (Pro/E is one I've seen used effectively). I've also even seen very astute users build simplfied representations into the original CAD models. We're going to see more of this kind of intelligent design/manufacturing integration in the future, I hope.

For a complex agglomeration of parts (like an entire engine) we would use a number of tools, including shrink wrap, to simplify some features, perhaps on a component-by component basis. Patch independance at least means you don't have to do all the clean-up at the CAD level.

Other things worth considering: For very complex parts, sometimes STL representations are easier to work with, as the CAD representations can become unweildy. ICEM CFD has very tools for simplification and repair of STL models as well. Also, the Hexa mesher, with which the user builds a block-structure which is related to the CAD model, has proven an effective tool for CAD simplification. With it the user can select which features to capture, which to ignore, where to project to the underlying surface, and where to simply interpolate between the block edges. The simplified 'mesh' is then used as a discrete geometry representation.


Judd Kaiser November 20, 2001 13:54

Extracting surfaces in ICEM CFD UG direct interfac
 
In general, the solids aren't 'destroyed', but are just blanked.

Alternatively, you often don't need to extract surfaces, but can add surfaces to the ICEM CFD model using 'select solid' when defining families.

If you choose to extract surfaces, the advice we usually give is to use UG to exctract the surfaces using 'Insert, Form feature, Extract' to extract surfaces from the solid.

If this isn't clear please feel free to send a request to 'support@icemcfd.com'.

wulf November 20, 2001 14:04

Re: ICEM-CFD - Catia Interface: anybody experience
 
Hello Jonas,

That's whey we put the projection limit option into HEXA. It allows to pack the grid within the limit defined without reflecting disturbance from the side surfaces.

Best regards

Armin

Jonas Larsson November 20, 2001 16:14

Re: ICEM-CFD - Catia Interface: anybody experience
 
Yep, and as I wrote below it also seems to solve my problems. ICEM Hexa is wonderful once you learn all these small tricks.


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