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No rating yet Subject: Re: IGES import with subsequent creation of a Solid model Author: John Crawford Date: 2000-10-11 21:38:00For more info on XOX you can go to their web site www.xox.com and check out their stuff. They list ANSYS Inc. as a customer in their "Partners" section.
I seem to remember that XOX entered the ANSYS universe when 5.0 hit the streets in 1991 or 1992. ANSYS wanted a smarter modeler than the one they had in 4.X and instead of starting over they obtained the XOX engine and integrated it's boolean functionality within ANSYS. The big problem is that native ANSYS geometry is in one form (b-spline, nurb, whatever...) and XOX wants something else, so every time ANSYS performs a boolean it has to translate native ANSYS geometry into XOXese (for lack of a better term), have XOX import it and do the boolean, then export the booleaned entities and translate them back into ANSYSese. It doesn't take a rocket scientist (although I'm sure several are reading this) to see that there are 3 places for failure to occur in this process; the first translation, the boolean operation itself, and the second translation. After you consider all that goes on beneath the sheets, it's not suprising that we see "Change BTOL and try again" as often as we do. I sometimes find it hard to believe that we've been having this kind of fun for 8 or9 years now.
I'm sure that others can add to this discussion, but this is my understanding of things.
As an aside to this, it appears as though the native ANSYS geometry needs to be REALLY precise, which explains the problem in doing boolean operations (the operation is only as precise as the engine that performs it) as well as ANSYS' difficulty in importing sloppy geometry files from such fine programs as CATIA. People tell me that geometry from Pro/E usually imports pretty well, and that may be because their geometry engine is fairly new and is "tighter" than the geometry engine in older programs like CATIA V4. I am curious how easily CATIA V5 geometry is imported into ANSYS. Has anyone done this yet?
Before anyone mentions it, yes I am reponding from home, and yes this means that I am sick and demented. I can't offer any explanation other than it's the only way I know how to be.
I refuse to comment on whether I am wearing bunny slippers as I type this.
John Crawford crawford@a...
----- Original Message ----- To: Sent: Wednesday, October 11, 2000 7:51 PM
> 'MicroTopololgy'. Yes, that's the word I was looking for. Thank you > for refreshing my memory regarding the faceted surface representations.
> You state your belief that:
> > Shapes has its own Boolean > > operations, and so does ANSYS standard modeler. Hence, if a user > imports a > > model that uses Shapes modeler, it remains in the Shapes modeler. > Likewise, > > if a user imports a model that is in the ANSYS standard modeler, it > never > > uses Shapes (XOX), but it only uses ANSYS standard modeler operations.
> Hmmm, if the ANSYS standard modeler has its own set of Boolean > operations, what purpose has the XOX modeler served over all of these > past years? It is my impression that ANSYS started using XOX many years > ago, perhaps in the late 4.x revs or at least in the early 5.x revs. > (XOX was a Minneapolis company, so I kinda paid attention to it for > awhile.) Surely the XOX Shapes modeler was essential for something, > prior to its being used for the "Allow defeaturing" form of geometry > import introduced at approximately rev 5.4?
> OK, have I beaten this topic to death yet? :-)
> Anyway it seems as though there is uncertainty within the user community > regarding how ANSYS handles solid geometry. (Or at least, Mark, you, > and I had somewhat different impressions as to how things worked.) > Would anyone at ANSYS, Inc. care to clarify the situation?