A Guide to CAD Translation Formats


I was talking to a fellow at a large NW aircraft company about sharing CAD files with different companies. They are always confronted with what format to send or receive the parts or assemblies. If you are creating parts in small company that only does initial design and rarely use outside parts this is not a problem and most any high or mid-range CAD system will do the job.  But if you are working with different systems, you either need to establish an import/export standard or have a product that can read, save and modify native files from the more popular products.

We are lucky to have the best History, Integrated Direct Edit and Hybrid modeling products available with IronCAD and ZW3D. Both products can read any of the popular CAD packages parts/assemblies indirectly or directly into a single file. Yes, you can read the assemblies, including all the parts into one easy to use file, and modify them as if they were created in any of these products. Try that with a Pro/e Clone, it loads up your hard drive with all of the separate part files, which in most case can only be used for reference. With our CAD products we offer the most interoperable capabilities available. So let's take a look at the translation options. I will not go into the history of these file types, basically just tell you where they come from.

Which systems have the best interoperability? The Worst to Best CAD System and Why


Dxf/Dwg: Autodesk

Dxf (Drawing exchange Format)/Dwg (Autocad file extension) Even though this is not a true standard it is used for most 2D (drawing) translation. In the past Autocad was the 2D CAD king and thousands maybe millions of drawings were created, and other programs used this format to utilize that data. Today this is the format used to translate drawings vector graphics between packages. All CAD packages include this translator in their packages. It is quite surprising that there has not been a more universal replacement.

Dxf/Dwg also bring in 3D wireframe and solids. I have not used it much, but I have brought in solids successfully.

IGES/.igs: National Bureau of Standards - The beginning of solids.

IGES (Initial Graphics Exchange Specification) was the first 2D/3D wireframe Translator. Years ago when working at Boeing we used this format to exchange wireframe between Catia and CADKEY. We could translate all Wireframe data. As it matured it could translate drawing, 2D/3D wireframe, surfaces and solids. Even though it has the ability to read and write solids, it is now used primarily to export and import surfaces. This package was used for years as the CNC, CAM or manufacturing standard. It is not the best translator in this world of solids. This package is included in all of our packages, but can be an expensive option for some other CAD packages.

STEP/.stp: ISO Technical Committee

ISO 10303 is an ISO standard for the computer-interpretable representation and exchange of industrial product data. Its official title is "Industrial automation systems and integration - Product data representation and exchange", known as "STEP" or "Standard for the Exchange of Product model data" Now, that's a fricking mouthful. LOL

This is basically the replacement for IGES, which I am sure they have stopped all development. We are hoping that STEP will be the future standard for all systems to import and export. Now with the industry moving to Explicit Modeling as the new standard we need a common translation format, including the PMI (Part Manufacturing Information) or Detail Drawing information. This would close the door on all the incompatibilities between CAD packages thereby reduce the incredible cost of being Lost in Translation. All of our products read and write STEP. All of the SOLID modeling packages both read and write STEP.

Now STEP is the real beginning of Solid Model Translation, even though it can be used to translate other data with all of the popular CAD packages. This format is the only to be used when work with companies that use the following programs.

As of this date Pro/E and Catia. Both of these programs only write out their solid models in this format. You export and import both parts and assemblies. I have read that Catia will be reading more standard formats and some native files from other popular CAD programs with V19. But for now use STEP.

ACIS/.sat: Dassault Systemes Spatial




This is the beginning of the solid modeling Kernels. KeyCreator, SpaceClaim and IRONCAD (also uses Parasolids) are based on the ACIS modeling kernel. Autocad is also based on a customized version of ACIS. This product was the first PC based solid modeling kernel. It is very popular and can be written and read by all the mid range solid modeling systems. It should be used when working with companies that use the following programs.

KeyCreator, Ironcad, SpaceClaim, Inventor (Earlier Version) or any other CAD programs that are based on this system, should use this format for any translations. I have found that ACIS has provided better results than parasolid in a few cases. It is interesting when using IRONCAD, I have resolved a few translation problems by using IRONCAD/INOVATE when switching between the two solid modeling kernels. I have received a few models in parasolids and the solids were corrupt and came in as surfaces and could not be fixed.

Parasolid/.x_t: Siemens Software

This is the other popular solid modeling Kernel. Solidworks and Solid Edge are based on Parasolids and it is the translator to use to when transferring data with these package. KeyCreator and IRONCAD include the parasolid translator, SpaceClaim offers it as an option. I have found mostly good results with Parasolids, but there have been a few very disturbing occasions that the model has failed to translate into a Parasolid based program. Since IRONCAD has both ACIS and Parasolid Kernels, we have had a chance to observe both Kernels strengths and weaknesses. Parasolid used to be the translator of choice but since Dassault has taken over ACIS it seems to be the more stable Kernel. This format should be the first choice when work with companies that use the following programs.

Solidworks and Solid Edge. This truly is the best format to use when exporting assemblies out of either of these programs. They will put the assembly in one file. As we have stated before all of our programs will import assemblies from these programs in one easy to use file.

Showing differences in Import Using Dual Kernel and Repair options.

JT/.jt: Siemens Software

JT (Jupiter Tesselation) is an ISO-standardized 3D data format and is in industry used for product visualization, collaboration, CAD data exchange and in some cases also for long-term data retention. Yeah, Right!!

I have never used this translator but is seems to have ties to PLM and able to be generated by the major packages with a certain level of compatibility and association. Sadly, trying to use translators as an engineering standard is a very poor solution, due to the requirement that they have to be saved in this format. I suppose it could be used with strict guide lines. But all getting on board would never happen. The arrogance of the high end CAD systems cannot be matched.

IronCAD Trans includes this format. ZW3D offers it as an option.

When in DOUBT!!

Direct Native File Translation

The best translation is direct native file translation. Both of our product offer access to all the popular CAD programs plus all of the standard neutral formats. You can import a part/assembly and translate it to a different format or modify the parts or assemblies directly. The assemblies come into one file so you do not have to worry about tracking parts.

Imports Creo (Pro/e), NX, Solid Edge, Solidworks and Inventor
Imports'/exports Catia 4/5

The Worst to Best CAD System and Why!

Universal CAD Compatibility is Here! 

Using Multiple CAD Systems

PMI (Product Manufacturing Information)

I thought I would move the discussion to PMI. Today many of the large companies are moving to MBE (Model Based Enterprise) and are using PMI to release their engineering documentation. This has caused a huge problem with duplicating our engineering documentation. The image below is a sample Catia 5 PMI file from a large aircraft manufacturer imported by ZW3D. The following article shows how this company is trying to utilize PMI, it is not a pretty picture.


PMI was developed to have a single document instead of having the separate AID (Associated Information Document) (drawing) at the time we were delivering paper prints. Sadly, the PDF was just around the corner basically eliminating any need for this format. This is truly a joke on the industry! Many still think we are delivering our documentation on paper, not for almost 20 years.

The problem is that the PMI is based on the native CAD file which cannot be standardized. Those that have developed this process do not understand the purpose of engineering documentation.

The purpose of engineering is to deliver concise, complete
and unambiguous standard documentation to manufacturing.

Today there is no free reader for this format. You have to have the native CAD software, a native CAD viewer or a third party reader/importer. This is causing very convoluted solutions. Boeing, having based the total authority of the design on the 3D model, now requires the supplier to purchase a 3rd party validation program ($5,000.00) if they are not using Catia 4 CNC. These hoops are costing Boeing a fortune as compared to the past with the standard drawing as the authroity.



PLM/MBE/PMI Absurdity!!

Can the 3D Model Be Used as the Design Authority?

This article is embarrassing in its ignorance.

Solidworks Totally Misunderstands MBD

TECH-NET does offer a very viable solution for reading and utilizing the native PMI.

Free PMI Importer?

Why buy a translator only package!

 When you can have a complete CAD package for the same price.

Starting at $2,000.00

Rental Starting at $375.00 for 6 months!

Import Solidworks, Inventor, Creo, NX and Solid Edge.

Includes PMI Import for Creo, Solidworks, NX and Catia!

Import/export Catia 4/5 and all the neutral formats.

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Joe Brouwer