The future of 3D???

[Iskit4iam]

I've been reading a few threads and they seeded some thoughts about the future of 3D CAD. I was wondering what others thought. And I was wondering if anyone knew of features in current systems that would address some of these issues.

Tolerancing: To the best of my knowledge tolerances get applied post model in the documentation, usually a 2D drawing. What system of tolerancing should be in 3D. How should it work?

One recent thread delt with a companies requirement for vendors to have Catia5 capability. Does the Catia5 model totally define the part?

Databases: One thread mentioned that a great deal of time was spent managing the model database. I've found this to be true in our projects, but this is not productive work. How can databases work better for users?

 

[swertel]

I tackle the first question.

Most 3D CAD packages allow you to specify the tolerance at the part level. When you import the model's dimensions, you also get the correct tolerance. Personally, although I'm quite young, I'm still old school in the fact that I need 2D orthographic drawings in order to see all the interfaces of mating parts. Sure, I can mate them up in an assembly, but is sure is easier to create section views on the drawing than in the 3D environment. And, it is at the assembly where I start thinking of tolerances, not when first concepting the part. To follow this thought to its end, since I first really LOOK at the interfaces of assemblies when creating the drawing, that's where I put my tolerances.

Question 2: I stopped using CATIA at v4.2.X, so I can't say with certaintude. I vaguely recall the direction they were heading, doubtfull they're there yet. My guess is that since they are a member of the ASME Y14.41 committee that they are moving CATIA to the paperless environment.

Question 3: The trick is finding a PDM system that integrates seemlessly with your CAD package and is fairly transparent to the user. Of course, you don't want the CAD package to suffer development issues in order to improve database issues. This is a fine wire to walk on.

--Scott

For some pleasure reading, try FAQ731-376

 

[warburton1]

I agree with Scott on the tolerancing issue, I would find it extremely difficult to start considering the application of tolerancing at the detail part phase. I also find it easier to play with stack ups with a drawing in front of me (on screen markups just aren't the same when your only doing it for yourself, gimme that red pencil ).

That said, Catia V5 has some very useful tools in the functional dimensioning and tolerancing arena (ANSI Y14.41 data). Also it would appear that dimensions and tolerancing could be applied at whatever level of the product you wished, part, assy etc. However, as usual with the bigger software houses it costs extra (approx $20000 PLC and $3000 ALC - values in Canadian).

We just had a demo by one of our CAD vendors on Catia's use in this arena, it seems good at it - however it was a sales demo!.

On the PLM front, one thing comes to mind, especially after all the fun I have had with Catia V5 and Matrix One. Try not to mix CAD and PLM vendors, one is always playing catchup with the other.

One final soap box issue, and maybe Scott would agree with me (being a fellow Alibre user). I would like to see the CAD software houses pull their finger out and agree on a standardized file format that would be ANSI Y14.41 compliant. As an independent contract design engineer the cost of Catia V5 plus all its add ons is prohibitive and as such I keep trying to get my customers to belay their demands for Catia output. If Step (possibly but not limited to) were more multi-functional then it could fill the need and open up the ability to transmit data between a larger supplier base (ie. not limited to eg. Catia users)

 

[swertel]

STEP is supposed to be the universal CAD data-sharing file type. There are committees galore working on developing this standard and its implementation. The only real thing keeping it from attaining its potential is USER adoption of it. All CAD packages I know translate STEP. Some better than others and that's why not all users choose STEP as their first data-sharing output. Since each CAD company makes their own translators that only give/receive so much data from the STEP file compared to their native format, most users pick another format that is closer to their native, such as parasolid.

The day that CAD companies and STEP can bring across feature histories is the day that it will get readily adopted. That day won't come soon because that will inevitably be the day that CAD companies can not longer compete (market their product) on their own proprietary data because they will be using the same native files. The only thing differentiating CAD companies would be their user interfaces.

To better explain myself, because there is obviously a difference between CATIA and BobCAD, take a look at Alibre. They started out using STEP as their native file format. As of v7, STEP is still a major portion of their file format, but they have gone to a proprietary format. Now other CAD packages will have to load Alibre translators along with STEP, IGES, SWX, SE, Parasolid, ACIS, DWG/DXF, etc. I can only assume they did this because they can then add their own information to the file and therefore develop their product on their own terms rather than the STEP committee.

--Scott

For some pleasure reading, try FAQ731-376