SolidWorks 2011 Parts Bible - Matt Lombard [301]
This translation depends on the version of the Pro/ENGINEER file. Check the SolidWorks documentation to see what versions of Pro/ENGINEER are supported.
Handling import errors
Import errors are usually caused by differences between the exporting and importing CAD software vendors. Some imports are more prone to errors than others. For example, the IGES format is interpreted different ways by different software vendors, and is, therefore, very prone to errors.
Another type of error is the error due to tolerance or accuracy issues. Catia is notorious for having very large tolerances on exported data. This is to enable Catia to work with large data sets more easily, but it means that when the geometry is read into SolidWorks, which typically requires more accurate data, you can see a lot of errors. The fact that the Catia to SolidWorks translation is one of the most problematic in the CAD industry seems odd because SolidWorks and Catia are both owned by Dassault Systemmes, but the difficulties have persisted for more than a decade, so it is not a technological difficulty, it is a business decision.
Repairing import errors automatically
SolidWorks has a tool called Import Diagnostics. Import Diagnostics can run automatically or manually to find the errors in imported data and to make repairs if possible. You can access Import Diagnostics by right-clicking an imported feature in the FeatureManager, as long as there are no native SolidWorks features that follow the imported feature. Figure 23.13 shows typical results from a faulty import.
FIGURE 23.13
Import Diagnostics helps you find and repair errors in imported data.
Sometimes the errors Import Diagnostics finds are things you can see, like missing faces, and sometimes they are things you can't see, like the edges of a face that don't intersect or inconsistent face normals. When errors can be found and repaired by Import Diagnostics, it is the best way to go. In fact, whenever I import a model, I always run Import Diagnostics on it to make sure everything is good.
Repairing import errors manually
Some errors are so big that the Import Diagnostics cannot fix them. An example of this type of error would be when a face is missing altogether from the imported data. When something like this happens, the only thing you can do is resort to surface modeling. If the import leaves you with surface bodies, and it cannot repair them automatically, you have to be able to remove the bad faces and replace them with new faces that you construct. This is all about using surface tools to create the new face, extending and possibly trimming the new face to fit into the gap caused by the bad face or faces, and then knitting everything together back into a solid. This may be an oversimplification of the workflow for manual import repair, but it is essentially the big-picture steps that you have to go through to get the task done.
There is such a thing as models that are so bad that you can't fix them, or that would not be worth your time to fix. If automatic repairs don't work, and simple manual repairs don't work, the next thing to do would be to go back to the source of the file and ask for better data.
Best Practice
Whenever you export data to another CAD system, it is considered best practice (and professional courtesy) to “round-trip” (save out, then read back in) the data to make sure that you can accurately read the data that you wrote out. You should not send someone else data that you cannot read back into the CAD system that created it. This may be of little comfort to you when you are the one receiving the bad data, but if you receive bad data, you have every right to go back to the creator and ask if he can round-trip his data. It might be that he can adjust tolerance or accuracy settings to give you better data, or possibly that his model had some problems that he didn't know about when he exported it out to you.
If you get bad data and you do not have access to the source, and automatic and manual errors prevent you from using