I have a SW file opened assigned as ModelDoc2 swModel.

I do some stuff, and ultimately save it as x_t, then load that x_t with:

ModelDoc2 swModelImported = iSwApp.LoadFile4(tempfile, "i", null, errors);

I then copy the imported bodies to my original swModel as follows:

          swFeatMgrImported = (FeatureManager)swModelImported.FeatureManager;

          swFeatImported = (Feature)swModelImported.FirstFeature();

            while ((swFeatImported != null))

            {

                FeatType = swFeatImported.Name;

                FeatTypeName = swFeatImported.GetTypeName2();

                if (FeatTypeName == "SolidBodyFolder" || FeatTypeName == "SurfaceBodyFolder")

                {

                    swBodyFolder = (BodyFolder)swFeatImported.GetSpecificFeature2();

                    Bodies = (object[])swBodyFolder.GetBodies();

                    for (int bodyid = 0; bodyid <= (swBodyFolder.GetBodyCount() - 1); bodyid++)

                    {

                        swBody = (Body2)Bodies[bodyid];

                        swPart = (PartDoc)swModel;

                        swFeat = (Feature)swPart.CreateFeatureFromBody3(swBody, false, (int)swCreateFeatureBodyOpts_e.swCreateFeatureBodyCheck);

                    }

                }

                swFeatImported = (Feature)swFeatImported.GetNextFeature();

            }

Everything works fine.  But technically, after this, I'm essentially done with the imported file.  So I want to close it:

iSwApp.CloseDoc(swModelImported.GetTitle());

From there, my original swModel is in a bad state (graphics area dead) and most of the time (but not always!?) SW will then crash.

If I avoid actually copying the solid/surface bodies from the imported file, everything is fine, and I can close the imported file OK. 

So I assume it's some sort of cleanup i must be missing after I complete the CreateFeatureFromBody3.  But it's unclear to me what it is.

Any ideas?