Why do you need to use the Import Diagnostics tool?

The Import Diagnostics tool is used to identify geometrical and topological errors in the model and repair those faults. This repair capability is needed because imported surface data often has problems that prevent surfaces from being converted into valid solids (because at the end of the day it’s the solid geometry that we need for product making). These problems may include bad surface geometry, bad surface topology, or gaps between the surfaces (sometimes adjacent surfaces have edges close to each other but do not meet, hence creating a gap).

After fixing these faults it then proceeds to knit the repaired faces with the rest of the surface body and if possible, automatically makes solid bodies from closed surfaces. It also converts any complicated B-spline surfaces into simple analytic surfaces for better performance.

Whenever you import a non-native SolidWorks model with faults, a message will appear asking if you want to run Import Diagnostics. Click Yes to activate it.

You can also automate this process in SolidWorks Settings. You can access the Settings from Tools -> Options -> System Options -> Import. Then select General in the File Format. There you will find Automatically run Import Diagnostics (Healing) and Perform full entity check and repair errors. Check these options and the Import Diagnostics tool will automatically start.

If you were not able to initiate Import Diagnostics during import, you can access it from Import Diagnostics present in the Evaluate Toolbar or go to Tools > Evaluate > Import Diagnostics.

Caution: It is critical to run this tool immediately after the import process is completed. The Import Diagnostic tool cannot be triggered if any other feature has been added to the Feature Manager Tree.

How does Import Diagnostics find problems?

Import Diagnostics runs various checks on the model to make sure that the geometry is not bad.

1. It runs the Check tool. You can access this tool manually from the Check option present in the Evaluate toolbar or go to Tools > Evaluate > Check.

2. It then runs additional checks to see if there are overlapping or self-intersecting surfaces.

3. Then it proceeds to replace complex surfaces that may reduce the performance of the model. Any planar, cylindrical, conical, etc. surface that is accurate but un-simplified B-splines present in the model are replaced with equivalent analytic surfaces, if possible.

Tip: For a coarse understanding, B-splines are surfaces that are made using splines and bezier curves while analytical surfaces are those that are made using lines, arcs, circles, fillets, and conics (ellipses, parabolas, and hyperbolas). If your model contains B-splines, that is not a problem as B-spline surfaces are also valid and sometimes even necessary. But replacing them with equivalent analytic surfaces improves performance and makes the model more usable in SolidWorks by making it easier for them to be used to create references. For example, you can’t create concentric mates to B-splines that are cylindrical. You can only use analytic cylinders for concentric mates.

How To Use Import Diagnostics Tool?

1. Import any non-native file type into SolidWorks.

2. If you used 3D interconnect to import the file you need to break the link in order for Import Diagnostics to perform the healing operation.

To break the link, right-click on the feature present in the Feature Tree and click on Break Link.

A SolidWorks warning will appear stating that this action can’t be undone. Click Yes, break the link. You will notice that the Feature Manager Tree now lists all the solid and surface bodies.

You can turn 3D interconnect off to get access to more options during the import. Go to Options -> System Options -> Import. Then select General in the File Format. There uncheck the Enable 3D Interconnect option to access additional settings such as if SolidWorks will try to form solids from the surfaces or just knit those surfaces.

3. Click on the Import Diagnostics tool present in the Evaluate toolbar or go to Tools -> Evaluate -> Import Diagnostics.

3. Import Diagnostics will perform all the diagnostics to find any bad geometry. It may take a while if your geometry is extremely bad or very complex. After this is done, you will be greeted with an Import Diagnostics Feature Manager which lists all the faces that have faults in them and all the gaps present in the surfaces that prohibit them to be converted into a solid body.

4. Click Attempt to Heal All to allow the Solidworks to automatically repair all the faults and gaps in the faces. Most of the time it is enough to fix all the errors but sometimes it may fail. And also if there are a lot of errors listed, then it may take a long time and sometimes may even crash the application.

5. Or instead, you can click on any of the Faulty faces listed in the table and it will get highlighted in the graphics area.

If you are wondering what’s wrong with this face shown above, then let us tell you that it is an un-simplified B-spline surface that can be converted into an analytical surface.

6. Right Click on any item to access additional options available.

• Repair Face performs repairs with the methods discussed above.
• Delete Face deletes the faulty face. If a face has too many faults to repair, you can delete the face and then use Surface tools to remodel a new face in the gap.
• Re-Check Face again performs all the diagnostics on the specified face and displays the result.
• What’s Wrong will tell you what is the error in the face.
• Zoom to Selection is pretty explanatory itself.
• Remove Face from the list allows you to keep the faulty face. It is mostly used to retain the B-splines from getting converted into analytical surfaces.

Import Diagnostics repairs face by doing one or more of the following:

• It tries to recreate the trim boundaries of the face based on the surrounding geometry. This method often fixes overlapping faces.
• It trims away defective portions of faces that are not used in the model.
• And the last resort is to remove the faulty face and use the gap repair algorithm to fill the resulting hole. 
• It also tries to replace any complicated B-spline surfaces with simple analytic surfaces for better performance.

All the faulty faces that are fixed, will have a green checkmark or they are removed from the list, and the number of faulty faces decreases.

Tip: The accuracy of B-spline surfaces that can be replaced is defined by tolerance of less than 10^-8. Searching for less accurate faces (between 10^-5 and 10^-8) would be extremely slow, hence prohibited. So if you think SolidWorks missed some B-spline surfaces, you can manually select those faces in the graphics area and click Repair Face to convert those faces to analytic surfaces if possible.

Now let’s head over to the Gaps between faces table.

Right-click on any item to access additional options available.

• Heal Gap attempts to heal the gaps with various methods as discussed above.
• Remove Gap removes every face adjacent to the gap.
• Gap Closer is a tool used for manually repairing gaps.

Import Diagnostics heals gaps between adjacent faces by doing one or more of the following:

• It tries to extend the two adjacent faces into each other to eliminate the gap.
• If there are two close and non-intersecting edges, it tries to replace those two edges with a single tolerant edge.
• If all fails, then it creates a Filled Surface or Lofted Surface to fill the gap.

To use the Gap Closer, right-click on any gap and select Gap Closer. In the graphics area, drag the gap edge handle with the pointer to the side of another edge. When the original edge turns green, right-click in the graphics area or the PropertyManager and select Finish Gap Closer.

Once all the faulty faces and gaps are removed, a green light will be shown under the Messages menu stating that No faulty faces or gaps remain in the geometry.