One area of SolidWorks that gets continued improvement over major releases is our ability to import geometry files and heal them with a high rate of success. In the event that imported geometry via STEP and IGES from other MCAD systems does not come in solid, your first course of defense is to use the Import Diagnostics tool which usually comes up by default when the import presents itself as a surface/s features in SW. Remember that the diagnostics tool is not a parametric/history based feature, and as such, you cannot undo its affect after you've completed its PropertyManager dialog. Many users ask why it has to be the first and only feature in the Feature Manager and this is the reason: because it is actually not a feature in the sense that all other features in SW are. Besides it's a rare occasion that you would not want to do an Import Diagnostics at the very beginning of your part - If you don't you could be in big trouble down the line as you try to build features on a corrupt part.
Gap Closer - Besides the automatic healing capabilities of Import Diagnostics, there are some lesser known, but useful features of it. In particular, the ability to correct corrupt vertex matching using the Gap Closer can be very useful. This is a rare occurrence, but when it happens, this tool is invaluable. The Gap Closer can be accessed by RMB on the problem gap listed in the PropertyManager list underneath “Gaps between faces.”
This tool gives the user the ability to correct for situations that the automatic import healer cannot deal with. It basically allows you to reconnect vertices of faces that are initially mismatched.
The Round Trip Trick - Another useful trick is when all else fails, consider a roundtrip back thru the import healer. This can be done by re-exporting the SolidWorks part as IGES and then re-importing the IGES file back into SolidWorks. By doing this, it gives the import healer sequential and successive attempts to try to heal your part. You might find after re-import, that new gap and face errors are listed in the Import Diagnostic tool.
Singular Face healing – Usually it is best to let the Import Diagnostics tool heal all faces that need to be healed all at once. But in some instances, this might not work because of the nature of sequential/successive heals mentioned above. An alternative to “round-tripping” your part is to partially heal certain faces and gaps and do this successive invoking the Import Diagnostic tool repeatedly. Rule of thumb in very troubled cases is to heal gaps first then go for the faces. You can do this by RMB over a particular gap and face and clicking “Repair Face” or “Heal Gap.” You might have noticed the “Color” option underneath the RMB – that’s very useful in these circumstances for identifying troubled or adjacent faces in your model that you want to keep track of.
Imported Units - Also a couple of other tips; sometimes parts can be exported from other systems with a discrepancy of the intended unit for the part. If you import your part and it comes in really small (or really big) chances are that it has been imported with the wrong units. This can be especially true if you decide to Insert a import feature into a current SW part. If this is the case, there is an opportunity to correct this when open or insert the imported file. In the open file dialog, there is an option button located at the lower left of the dialog. Click it and you can override the units parameters to correct this situation.
Delete Face – If you’ve gotten to the point where all the above fails (and believe me – I’ve been there) then your last course of action is to delete the corrupt face of the model and then using SolidWorks surfacing features to rebuild the face and Knit it to solid. Again the Delete Face option can be found by RMB over the particular face in the Import Diagnostic’s PropertyManager.
Hope this helps