CAD Translation and Repair: What you have or need?
by Robert A. Konczal, Chief Technical Officer, CATI
 

“Data Translation and repair costs the industry 20 billion dollars a year”, says an Industry study released in the last 12 months.   Are you surprised?  Don’t be-- the need to translate data between different systems can be a very costly and frustrating roadblock to successfully producing a product. The topic alone can be mind-boggling so I sought out to explain the process, terminology and options you have as a SolidWorks user while trying to maintain a readers’ digest format.

The fact that you are a  SolidWorks user is the good news.  The data translation capabilities and variety shipped with every seat of SolidWorks is very robust. The types of files that you can open (read/import) or save as (write/export) are in the following commands.  File:Open: select Types of Files:

For exporting or to send a file to another system from SW you will File:Save As. Note that depending on the file type you have active will determine your options.  Notice the difference when you have a part active versus an assembly or drawing.

These built in translators breakdown in the following categories: Neutral formats, Native/Direct, Graphics/Viewing formats.  Some native/direct translators can convert feature information (Sketches, dimensions, etc).  If features are required, all other translations efforts potentially can be enhanced with the use of FeatureWorks included SolidWorks Office and Professional or a solution partner product add on.  

Neutral Files Types

IGES (*.igs;*.iges)
The IGES format serves as a neutral data format to transfer the design to a dissimilar system. Translators, developed to the IGES Standard, are used to export a design into an IGES file for exchange and for importing the IGES file into the destination system. By far the most excepted format worldwide however, not necessarily the best. IGES stands for Initial Graphics Exchange Service. SolidWorks does not export drawings via IGES.

STEP AP203/214 (*.step;*.stp)
STEP (STandard for the Exchange of Product model data) or ISO 10303.  ISO 10303 is an International Standard for the computer-interpretable representation and exchange of product data. The objective is to provide a mechanism that is capable of describing product data throughout the life cycle of a product, independent from any particular system. The nature of this description makes it suitable not only for neutral file exchange, but also as a basis for implementing and sharing product databases and archiving.

STEP203 or ISO 10303-203 is an Application protocol for Configuration controlled design. In Industrial automation systems and integration of Product data representation and exchange. STEP214 or ISO 10303-214 is an Application protocol for Core data of automotive mechanical design processes. In Industrial automation systems and integration for Product data representation and exchange.

VDAFS (*.vda)
VDAFS is a neutral file format for the exchange of surface geometry. The VDA Surface Data Interface (VDAFS) was defined by the VDA (Verband der Automobilindustrie) to eliminate the deficiencies of the CAD interface IGES in the conversion of complex 3-dimensional geometry. VDAFS offers the technical conditions for the direct exchange of data between the CAD systems of the automotive industry and its suppliers. The emphasis of VDAFS is on the exchange of surface data, for example the data concerning the car body, large tools, injection mouldings, seats, glazing and the lights of a car.

Parasolid (*.x_t;*.x_b;*.xmt_txt;*.xmt_bin)
The Parasolid translator exports SolidWorks part or assembly documents as Parasolid text files or binary files and vise versa. Binary files are smaller than text files, but binary files are not supported in some target applications. Select the type supported by the target application.

ACIS (*.sat)
(.sat) The ACIS translator imports ACIS part or assembly files as SolidWorks part or assembly documents. The ACIS translator exports SolidWorks part or assembly documents as ACIS files.

AutoCad / MDT: DWG (*.dwg) DXF (*.dxf)
The DXF/DWG translator imports DXF or DWG files, including Mechanical Desktop files, as SolidWorks part or drawing documents, according to the option settings in the DXF/DWG Import Wizard.  This translator also imports DXF 3D files without the wizard. In a drawing document, you can import the geometry to the drawing sheet or the drawing sheet format. Entities in either paper space or model space are imported. The DXF 3D translator extracts ACIS information from a DXF file, if that information exists in the file, and imports it into a SolidWorks part document. If a DXF file contains multiple bodies or an assembly, SolidWorks creates an assembly document.

The MDT translator imports part and assembly information from Mechanical Desktop (MDT) files as SolidWorks part or assembly documents. You must have MDT installed on your desktop, but it does not have to be running, to use the MDT translator. The MDT translator is integrated into the DXF/DWG translator in the SolidWorks software, and is always available when you select DXF (*.dxf) or DWG (*.dwg) under Files of type in the Open dialog box. The DXF/DWG exporting translator only supports drawing documents as .dxf or .dwg files.

Native or Direct Files Types

ProE Part (*.prt,*.prt.*;*.xpr) ProE Assembly (*.asm;*.asm.*;*.xas)
The Pro/ENGINEER translator imports Pro/ENGINEER part or assembly files as SolidWorks part or assembly documents. The attributes, features, sketches, and dimensions of the Pro/ENGINEER part are imported. If all of the features in the file are not supported, you can choose to import the file as either a solid body or a surface model.  The Pro/ENGINEER translator supports import of free curves, wireframes, and surface data. Limited to version17 through 20 until further notice. The Pro/ENGINEER translator exports part or assembly documents as Pro/ENGINEER part or assembly files.  The exported files are saved as Pro/ENGINEER version 20 files.

CADKEY (*.prt)
The CADKEY translator imports CADKEY part and assembly files as SolidWorks part or assembly documents. The CADKEY translator supports import of surface or solid entities from CADKEY version 19 part or assembly files.

Inventor Part (*.ipt)
The Inventor Part translator imports Autodesk Inventor part files as SolidWorks part documents. The imported part files contain only geometry; features are not imported.

Solid Edge Part (*.par)
The Solid Edge translator imports the Parasolid information of Solid Edge parts into SolidWorks parts. Only the Parasolid information is extracted, not the feature information of a Solid Edge part. The Parasolid translator imports Parasolid information from Solid Edge parts up to and including the most current version of Solid Edge.

Unigraphics aka UGII (*.prt)
The Unigraphics translator imports the Parasolid information of a Unigraphics II part or assembly into a SolidWorks part or assembly document. Only the Parasolid information is extracted, not the feature information of a Unigraphics II part. You can import parts and assemblies from Unigraphics II version 10 and higher.

AutoCad / MDT: DWG (*.dwg) DXF (*.dxf)
See above topic in Neutral File Types.

Graphics, Polygonal, or Viewing Files Types

STL (*.stl)
Primary used for Rapid Prototyping but can also be used for Analysis/MoldFlow programs and some manufacturing applications. The STL translator exports SolidWorks part and assembly documents as STL files. These types of files are also known as faceted volumes.  They are an approximation of the precision model.  The STL translator also imports STL files as SolidWorks part documents. SolidWorks assembly files that you export as STL files import into SolidWorks as part documents. You have the option to import STL files as graphical data, solids, or surfaces. When you import STL files as graphical data, you can select the Import texture information check box to import texture information if this data exists. 

VRML (*.wrl)
VRML files can display 3D graphics over the Internet. The VRML translator imports all VRML files as SolidWorks part documents. SolidWorks assembly files that you export as VRML files import into SolidWorks as part documents. The VRML translator attempts to knit the VRML polygons into a solid. There are no contoured surfaces in the imported file; all surfaces are planar (same as STL file ). This import option is intended as a last resort for importing data into SolidWorks.  You have the option to import VRML files as graphical data, solids, or surfaces. When you import VRML files as graphical data, you can select the Import texture information check box to import texture information if this data exists. The VRML translator exports SolidWorks part or assembly documents as VRML files. When you export as a VRML file, the SolidWorks software takes the View, Display, Section View option into account. If Section View is on, only the visible geometry is exported to the VRML file. This is different from the way the software behaves when you save documents as IGES, STEP, Parasolid, or ACIS files.  When you export SolidWorks documents as VRML files, you can choose the version to export, VRML 1.0 or VRML 2.0 (VRML 97).

Catia Graphics (*.cgr)
The CATIA Graphics translator imports CGR files as SolidWorks part documents. CGR files contain only graphical information and are for viewing only. The CATIA Graphics translator exports SolidWorks part or assembly documents as CATIA graphics files that users can view in CATIA, CATweb, and DMU Navigator.

HCG (*.hcg)
The Highly Compressed Graphics translator exports SolidWorks documents as Highly Compressed Graphics files. HCG files, used by CATIA in CATweb, are optimized for transmission over the Web. You can export only parts and assemblies with the HCG translator.

Tif (*.tif)
You can import a TIFF image as a background into part or assembly documents. SolidWorks does not support LZW format compression for TIFF files.  The TIFF translator exports any SolidWorks document as a TIFF image. You can capture the image as it appears on a normal view (screen), or you can capture the image as it appears on a print preview. For drawing documents, you can select the sheet size and scale factor.

JPEG (*.jpg)
The JPEG translator takes a snapshot of anything displayed in the graphics window of a SolidWorks part, assembly, or drawing document, and exports it as a .jpg file. A .jpg file is an image file that you can open in most image viewers. The .jpg file displays only the information from the graphics window; toolbars and other areas of the SolidWorks window do not appear.

HOOPS HSF (*.hsf)
The HOOPS translator exports SolidWorks part or assembly documents as HOOPS (.hsf) files. HOOPS files are streaming graphics files that download details piece by piece to a web page, which is helpful when you display large files. You can view HOOPS files over the Internet using the HOOPS viewer. See www.hoops3d.com for information about the HOOPS viewer. The exported files contain graphical information only; you cannot edit these files. The HOOPS translator exports SolidWorks documents as HOOPS version 7.0 files.

RealityWave ZGL (*.zgl)
The ZGL translator exports SolidWorks part or assembly documents as RealityWave's ZGL file format. After you export the document, you must save the ZGL file into a RealityWave® database (VizStream Server). This converts the ZGL file into RealityWave’s streaming format that you can view over the Internet with the RealityWave viewer. The exported files contain graphical information only; you cannot edit these files. The ZGL translator exports SolidWorks documents as RealityWave version 2.0 files.

Viewpoint (.mts)
This add-in module exports SolidWorks part or assembly documents to Viewpoint files. You can view Viewpoint files over the Internet using the Viewpoint viewer. The Viewpoint files contain the compressed geometry of the model. The Viewpoint translator also creates an .mtx file, which is in XML. This is the animation and attribute file of the model. The exported files contain graphical information only; you cannot edit these files. The Viewpoint translator exports SolidWorks documents as Viewpoint version MTS3 files.

Additional Translators as Add-ins for SolidWorks

There are other options available to you other than SolidWorks out-of-the-box translators.  For instance, if you have a client that requires you to open a CATIA v4 file, what will you do?  The reasons will vary why they require this but if you want their business you will need to open this file.  SolidWorks solution Partner program has numerous options for you and CATI can help you select on that meets your needs. 

Here are the three main questions that most people should ask when you are researching a translation method.  Do you need to read and write or just read the cad specific data.  Second, do you need to maintain features or just translate geometry?   Third, what is the version of the other CAD system? 

It is important to know whether you have to read or read and write. Some translators only go one direction and most have addition costs for both directions.  If your client says you need to read CATIA v4 and deliver the job in CATIA v4 format then you are talking about two translators.  Or do you need to do the job in CATIA? In most cases you will not have to buy the other CAD system.  However, before committing to the job you need to ask a few more questions.

Second issue concerns features or just geometry transfer. In most cases, the client will only need you to deal with the “dumb” geometry.  This is the volume separate from all design history.  It comes into SW as one feature versus separate items per feature.  You can experiment by taking any part and save as a parasolid type.  Go to file open and read the file into SW and you will see the feature tree be reduced to one feature. 

If the client expects feature-rich data then your options are now down to very few offerings: Specialized Feature-Based Translator, or Service equivalent, or get yourself the same CAD system. The slamdunk comes if you need full associativity between parts/assemblies with drawings—this will require the use of the native cad system.  Currently, 2d drawings are not connected even via direct translators. The common practice is not to expect associativity and send DWG/DXF files of the drawing separate from the 3d dataset.

Third, what version of the other CAD system are you expected to be compatible?  There are many translators available but not all versions are supported.  Using our CATIA client from the earlier example, is it v4 or v5 of CATIA that you need to read/write?  These are typically two separate translators you may need to purchase. 

Here are some additional issues about translating directly from one system to another.  Some translators work inside the CAD systems.  Therefore there may be a component to send a file and then the receiving system may also need a software component.  This can force you into a difficult spot if you do not have access to the originating operator/cad system. For example, if you’re a sub-vendor you may be out of reach to request this cooperation. 

Final thoughts on specialized and direct translators.  From my experience, the investment for a direct translator is typically a business decision more than a technical decision.  The point being, if you are not going to get work from a client because you don’t have the same CAD system buying this translator can bring in more business for your organization.  On the same point, it can be a competitive advantage for your organization!  Also, set your expectations accordingly, nothing is perfect and therefore budget for the ongoing support and maintenance to make sure you can get all the help at the proper time.

Geometry Repair and Improvement Add-ins for SolidWorks

When dealing with imported data there will be issues from time to time.  The old saying goes, “Garbage out then Garbage in”.  This is not an exact science and therefore things will happen that will be very difficult for the common user to repair—hence, the 20 billion dollars lost a year in data translation!

When translating between two systems there are accuracy issues, missing entities, unsupported entities, mathematical errors, formatting issues that potentially can cause things to go a stray.  Therefore, there are many things SolidWorks has done with their translators to accommodate these issues in the base software.  However, there is a point at which the damage is beyond automation and you will need to manually interact with the data to achieve proper results. 

The most common issues fall into a few categories; surfaces not knitting into a solid or to each other, solids with bad faces or gaps, or missing data—it happens!  There are many tools in SolidWorks to detect these situations but not many to quickly repair or improve them.  I recommend FormatWorks as a tool to review and understand. 

FormatWorks, A Gold-Solution Partner of SolidWorks, offers three main additions to SW.  It gives you another IGES reader with geometry checks, automatic repair and healing automation routines, and Quality improvement tools that enhance SW base translators.

 Automatic repair and healing comes with numerous features. One example that will be very common if you deal with CATIA data is their ability to simplify Nurbs data. In the above example when reading the file with SW IGES turned into 322 surfaces as a result, with FormatWorks IGES turned into 79.

As mentioned earlier, accuracy is one of the most common issues where translating data can cause heartburn.  There is very little SolidWorks can do if the accuracy is not in the incoming IGES file--so what will you run into? 

One common issue will be gaps in the file causing it to disable you from working with the part by not allowing you to do additional commands in SolidWorks.  Here is a simple example of what can cause you to lose time.

These types of issues are not always apparent after importing the file into SolidWorks.  So here are some recommendations for you to do each time you have read a solid or series of surfaces into SolidWorks.

 If there is a Red ! like :  Houston we have a problem!  Next you need to select the Imported1 icon with the Right mouse button (RMB) and select Diagnosis and the menu to the right with come up. This tells us we only have one bad face. In most cases fix faces option will have little impact at this point and we will need to do delete and recreate the face.  FormatWorks can eliminate the tedious process of doing this and will automatically knit the remaining surface into a solid. 

A more common scenario is to our left where the model didn’t knit into a solid.  This example has 591 surfaces to form a solid.  One surface missing can make or break it coming in as one imported solid.  FormatWorks reduced this potential nightmare into 10 minutes of repair work.

Summary of Translators and recommendations for SolidWorks.

The following chart includes a summary of capabilities by default.  I have also included alternative suggestions to get to/from other CAD systems.  These recommends also include add-in tools from Solution Partners.  This is only an overview--Keep in mind that versions can play a big factor towards success.  There is not always one answer to each scenario so don’t hesitate to experiment if time permits or call upon CATI for assistance.

Key: X = Default SolidWorks, N/A = Not Applicable or available, NF= Use a Neutral file format, DT= Direct Translator Solution Partner add-in, or a Specific translator type as an alternative.

Note1: 2D geometry can exported via IGES/STEP via a looping process . However, the annotations and dimensions will be ignored.

Note2: If they are converted to TIFF format they can be read in as background images. There are several programs that canconvert a JPEG to TIFF—external from SW.

Note3: Standard Windows functionality allows you to import a graphics format like JPEG or TIFF in to SW Drawings with Insert|Object. 

If you have a situation that you would like to discuss feel free to contact me at bobk@cati.com.  If you would like to learn more about FormatWorks see attached demo video to this newsletter or contact me to setup a webex.