SW2004 Loft Weirdness

Paul,

it gets even scarier when you think about doing some modifications to a $100,000 mold.

You design and build the mold from 2003 data. Six months or a year later you have to add a feature that blends with a complex surface. Problem is, the product and mold data have been converted to 2004, and the converted mold components no longer represent the parts you made. You're screwed ! The only way you can do it is to have a copy of the original, in the old format, and a working copy of 2003.

Or you could (if you were clairvoyant) have saved the data in Parasolid before translation, but this kinda defeats the whole purpose of using a system like this.

I really don't think they're thinking things through very well at SW. At least from a practical viewpoint.

Regards

Mark

Strange thing.. I just got this email from CADCAMNET on a new article they published...

"With Inventor release 8, Autodesk has slashed the time needed to rebuild models. However, some customers may find that models made with previous releases don't work right in the new version."

I won't comment.

Mike Wilson

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Mike,

Yea, read the article.

It seems IV7 parts, created with simple analytic features, are comming into Ver8 AFU. At least with SW it's the lofts, sweeps, and surfaces that get hosed....

Yknow... somehow that doesn't make me feel better.

Mark

Right-on Paul. Thanks for the link. That was some article. It has a sad ending though...

"In fairness to Autodesk, users of other CAD software, including SolidWorks and CATIA version five, have complained that geometry sometimes changes when parts are upgraded from past software releases."

Makes me wonder where they gor that info from.

Mike

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Yeah, makes one think about all these companies cashing in on modifying, breaking and fixing these Umpa lumpa algorithms per release?

Making all those next release promise investors and job security minded people smile from ear to ear.

Cha-ching!! $$$$$$$$$$$$.

..

"Mike J. Wils>

Ed,

I was not really aware of this so thanks. I suppose that could be one factor in the bloat of the software.

Even so, if I had to reproduce from scratch a particular loft in a new release I might not be able to do it and get the same results. Ditto for repairing.

I am all for archiving complex geometry as parasolid or iges.

I remember back in my early days working with ANSYS. There was a splash screen on login that stated ANSYS was certified to meet certain standards of accuracy. In almost any engineering discipline there are standards to meet. ANSI, ASME, NFPA, ASTM, ISO, DIN, etc. etc. Where are the CAD standards? And more important, where are the CAD software houses that would own up to a standard?

Edward T Eat> Paul (and others),

Hi there Mark. Well put!

But, if you did translate something into a CAM system, wouldn't you have some geometry artifact in CAM that could be used in a model to model overlay?

Additionally if the cad model that generated the model were managed (released and locked) the "no geometry" to compare problem would be lessened.

I think your scenario you mention could be very real and dangerous, but especially if the CAM system works only on native data (I.e. no geometry artifact native specifically to the CAM system). If it generates a snapshot of the geometry then a record for comparison would exist.

Your point about actual capital equipment being at stake is right on. We are not just dealing with electrons but with metal which is generally less cooperative when things go awry.

In any case, perhaps what the program needs is a model level switch to "Lock Legacy Data" or a "Recreate Legacy Data With Legacy Algorithms".

I agree with your "not thinking it through too well" comment. This is professional level stuff and needs to be stable - there is more at stake than a cad model - it's all the stuff that gets made from the cad model.

The real world need for PDM (i.e tracked & recoverable history - I'm a believer) rears it's ugly head once again.

Regards,

SMA

That's why there is some merit to archiving neutral (parasolid) versions of geometry that tools are made from.

There is a point in many products' lifecycles where feature data can become obsolete. Ultimately, it's the geometry that must rule, not the features.

I do maybe 10 (very simple) lofts a year. I have one that fails on rebuild in 2004 despite working in 2003. In fact, it loads in 2004 fine, and doesn't fail until a rebuild takes place.

Jim S.