MicroStation can control the display of filled elements and patterns separately in the View Attributes dialog, but AutoCAD has only one system variable FILLMODE that controls both the parameters. When FILLMODE is turned on, both filled and hatch areas are displayed in AutoCAD. When FILLMODE is turned off, neither is displayed. For DWG compatibility, Fill and Patterns should be set to the same state - both on or both off in the View Attributes dialog. However, if you have a DGN file that has Fill and Patterns set differently, and if you save your DGN file as DWG, you should expect the following cases:

1. Fill on and Patterns off:
   • Select a valid view for Source of Level Display in the Save As DWG/DXF Options dialog.
   • Patterns in active file will not be saved in the DWG file, retaining the display of patterns turned off.
   • Patterns in reference files will be saved regardless of the View Attributes of master file, but FILLMODE will be set based on reference file's Fill/Patterns state in the output DWG reference file.
2. Fill off and Patterns on:
   • Select a valid view for Source of Level Display in the Save As DWG/DXF Options dialog.
   • Patterns will be saved in both active and reference files.
   • FILLMODE will be turned on in the output active DWG file (that is, you will see Fill turned on when you open the saved DWG file).

The following setting is added to the Save As DWG/DXF Options dialog:

• Set Block Units From File Units