Here's another what annoyed me today thread...

I'm currently trawling through some CAD data that got sent to us by a consultancy. Since we've had the work done, we need to change the size of the components, but i'm now faced with picking through the history tree and deciphering the thought process that went into designing these parts so I don't screw anything vital up!

Just an observation - isn't it weird that no two people will design something in the same way, and is there anything more frustrating that trying to think like another person when editing their work!? Tempted to start it again and do it my way!

That is all!

P.

 

That's one of the many reasons I dislike history based modelers. Even if you did the original design yourself, you can find yourself stuck and have to re-model it from scratch.

You don't have this problem with direct modelers like KeyCreator or CoCreate. I've never used the latter, but with KC any imported solids are indistinguishable from solids originally modeled in KC... and you can easily modify anything.

 

No problem with CoCreate either. Give me a sat, iges, step etc and it thinks it created it from the get-go.

 

My biggest issue with trying to access CAD data provided by others is FORMAT. If one does not have available the particular package in which the information was generated, one faces quite a few access issues. Even when the designs are exported to "standard" formats (*.iges, *.stl. *.stp, etc.), there can be a loss of data, elements can be distorted or displaced, dimensional data lost. Most of the major packages appear to want to force users to using their particular package (this appears especially true of Autodesk and Solidworks, the two I most commonly encounter). Even with supposed "open" formats such as *.dxf, one encounters difficulties, since the format seems to change almost annually, and newer drawings can not be accessed with older versions of the software. I do not have sufficient resources to dedicate to multiple high-dollar design packages, and I find it oven more efficient timewise to request the drawings in *.pdf, and then recreating the parts of interest to me in my own choice of CAD packages. Apparently, some of these "super" packages have no problems importing my *.dxf or *.dwg contributions, created with inexpensive or OpenSource packages- an interesting situation. I can give, but I can't receive!

 

HI Guys
I am working on Pro/e from last ten years, Catia from last three years and worked on other CADs too. There are two types of scenarios we faced when we get data from other users. 1) Data in same format & 2) Data in standard exchange formats.
1) most of the times I am able to edit the data, just I need to check carefully how other user model it.
2) most cases, we cant edit the data in history based modelers (but we can make new model by reusing the geometry), but in free synchronous modelers, it is also very limited area anyone can edit. For example you can move features like holes, chamfers & fillets etc and make straight pockets or bosses big or smaller. But you cant edit a curvy surface feature.
What other problems you guys mentioned here are same. Actually some peoples and companies also don't want to share their model history too. They think, no body can do whatever they did. We have Pro/E, Catia, Powershape, Powermill & MasterCAM. Pro/e and Powershape is the most common used systems here. The people have Pro/e are not providing pro/e format too. They knows we have it but they always sending iges or stp format. So in this scenario, what anybody can do.................??

 

Translatability issues are on many levels. Basic solid model shapes generally translate quite well, but information attached to the solid (like threaded holes, etc.) is lost, as is any history or parametric information. Translation is better when both the sending and receiving system share the same core engine (e.g. many CAD packages use the ACIS core, while others use the Parasolids core).

On the drawing and annotation side, it's not as good. Many if not most CAD vendors use their own proprietary format for dimensions, and they will often come in screwed up, or looking perfect but burst apart into individual lines and text instead of an associative dimension entity. The solid-drawing relationship is also often not preserved.

Note that dxf is not an "open" format; it's an AutoDesk proprietary format. The only truly "open" formats are IGES which is rather old, and STEP. Others, like SAT or XLT, are connected with their associated core engines (ACIS and Parasolids, respectively, in this case).

Even for internal use, we use pdf for drawing archives, guaranteeing that the drawing will be readable and look the same no matter who's looking at it. We save the CAD drawing file too, of course (with KeyCreator, it's part of the model file), and use that as the basis for a new exported pdf when the drawing is revised.

Although I frequently use imported solid models (mostly downloaded vendor data or customer parts) in my design work, I never have to edit anybody else's drawings, so annotation issues are rarely a problem for me. On rare occasions I'll need to use somebody's 2D drawing geometry to build a new solid model... but fortunately less and less people are still in the 2D stone age any more.

 

The CoCreate world is wonderful for importing STEP AP203/214, IGES, and saves as if the data was native. The lack of a history tree, in simple terms, makes it possible.

Since being created by HP as Solid Designer, the company was spun off as a new business known as CoCreate. Subsequently the name of the 3D portion has changed to Cocreate Modeling, and will soon lose the Cocreate tag. Parametric Technology Corporation (PTC) of Pro-E fame purchased Cocreate and the name is changing to PTC Creo Elements/Direct. Unfortunately the announcement came in 2010 yet the new product won't be available until mid 2011. It promises to be the part of PTC's solution to address the non-history based 3D CAD.