Solid prt file and asm files after saving into stp changes into surface

[ashmech007]

Hello Everyone,

I am facing an issue, while saving .prt file into .stp file in creo M120 everything comes in surface .No solid I can see

But the same .stp file while I open in catia V5 it comes correct.

Any setting or visualization issue which I need to set in creo.????

File attach below

Thanks

[KenFarley]

Whenever I see this (often, with parts downloaded from suppliers) it usually means the surfaces are non-manifold, meaning they don't completely enclose a solid volume. Looking closer usually shows a gap in two adjacent surfaces, an improper trim, or some other "failed" geometry manipulation.

There are some ways you can try to correct the problem:

(1) Use the Import Data Doctor to "redefine" the imported feature. Sometimes this can be relatively easy, other times it doesn't work.

(2) You can play around with the Accuracy settings for the part file, and that sometimes lets the geometry be created in a "good enough" state. Not perfect, but it sufficient to move the project along.

As far as Catia being able to read things fine, no surprise - all the high-end CAD packages have their strengths and weaknesses with surfacing. The underlying root of the problem might be that the STEP file has a type of surface that is perfectly okay for Catia but Creo has to interpret it as a type of surface that it is capable of handling, introducing inaccuracies, etc. I just recently had to resort to sending some files to a different division so they could manipulate them in Rhino and fix a nasty non-tangency - stuff I couldn't do, despite a lot of swearing and button mashing, with Creo.

[remy]

Data exchange is a fascinating topic.

To top your contribution, there is a slight difference between the manifold property and the watertightness of a solid. 

On one hand, the watertightness is related to the smallest gap being tighter than the accuracy set in the model. 

On the other hand the manifold property has more to do with the logics of the entities. It is about surface being oriented properly for example, or whether all edges are linked to only and only a pair of surface edges.

ie a model can be watertight although not manifold. 

I have to agree that all CAD solutions have strenghes and weaknesses. Creo has always offered good performance data exchange wise overall (from my experience being at PTC and off PTC). 

One also has to consider the history of model. You can have a hint of it by editing the model with notepad. The CAD generator is listed in the STEP definition.

Asking any CAD to read any STEP files generated by any CAD is wishful thinking but in reality some CAD, in some instances are not able read the STEP they generated. 

CAD Data Exchange is not a trivial topic (some people describe CAD healing as CAD surgery) and at the same time, it is very pragmatic: you need to try everything.

Finally IDD is the tool of choice to "repair" the model. Here is an article https://www.ptc.com/en/support/article?n=CS291988

[Pettersson]

That article is neat, but it's horribly out of date. The majority of the tools that are referenced don't seem to exist anymore?

[remy]

The article refers to a "Suggested Technique" which indeed was written some time ago.

Feel free to share your opinion and improvement suggestions by clicking the portlet "Was this information helpful?" and we will deal with it accordingly. Please be as accurate as possible.

[ashmech007]

Yeah ,I found IDD useful,but I have big asm and prt files which after doing IDD showing 1077 errors which is not only much in number but also time consuming if I going to correct it .

It is good If we are just starting modelling and then time to time we check our model on IDD .

I fave full powertrain product which If I do IDD then it takes a month to solve all.

Is their any other way round to fix the issue.

[remy]

This looks indeed like a lot of work and time consuming.

With this amount of errors, i recommend to revise your import process.

Can you supplier provide you with the original model instead of the STEP file for example? 

Did you try importing the native file instead of using STEP file format?

If you think this is relevant file a support case so that TS can look into it in details.

[ashmech007]

I have original file and I am trying to generate solid from that after modelcheck.

[remy]

When you say "original file" do you mean the file before it was a step file?
If yes, what CAD is it? Why didn't you try opening it directly in the first place?

[ashmech007]

user would like to convert it into prt to stp .And such situation we are getting

[remy]

So if I understand your workflow properly:

1. assembly is created natively in Creo

2. Creo model is exported to STEP

3. STEP model is import in Catia V5

Can you confirm or correct?

[ashmech007]

workflow is like that 

1. assembly is created natively in Creo

2. Creo model is exported to STEP

3. STEP model is import in Creo itself but everything converted into surface 

[remy]

Thank you for clarifying. 

Even though i understanding your reasoning, exporting to STEP or IGES and importing it back does not tell anything relevant about Creo's performance. It is called the "loopback" or "roundtrip" test.

Please find some articles about this:

• Guidelines to handle data repairing
• Solid part file exported as IGES/STEP with export option as “Solid” is no longer solid when importing back

Users commonly make the assumption that importing and exporting to STEP is symmetrical. Even worse users tend to think that both works the same or have been designed by the same developer.

As a former CAD data exchange developer i can assert  that in reality importing and exporting are two different projects and have their own stakes. 

All the more the purpose of data exchange is to start from one CAD and move to another one not to come back to the original system. Industrially, the latter does not make any sense.

here are viable alternatives to your question: 

• Does Catia V5 offer a native Creo import? Did you try  it? 
• Did you file a ticket at Dassault Support desk?