Hello Jeremy,
OK, I found this method under [https://forums.autodesk.com/t5/revit-api-forum/how-change-the-color-a-element/td-p/5651177] which sort of works:
Color color = new Color(0, 0, 0); // RGB (0, 255, 255)
OverrideGraphicSettings ogs = new OverrideGraphicSettings();
ogs.SetProjectionLineColor(color);
ogs.SetProjectionFillColor(color);
ogs.SetCutFillColor(color);
ogs.SetCutLineColor(color);
doc.ActiveView.SetElementOverrides(fiProfile.Id, ogs);
The problem is my ELement is a Family instance of a Sweep. So the Projection lines are in the right Color, but the Element itself is not really a solid, but just a composite of the projection lines. Thus the question becomes, how can I convert a FamilyInstance of a Sweep into a solid?
Regards, Dirk