Thanks for your tests. I updated the program to ignore the drawing mode in SunFlow and in OBJ export.
I also renamed [font=courier new]com.eteks.sweethome3d.j3d.ignoreDrawingMode[/font] as [font=courier new]com.eteks.sweethome3d.j3d.drawingModeEnabled[/font] that has to be set to [font=courier new]true[/font] instead of [font=courier new]false[/font].

No idea if I'll go further one day with this drawing mode, handling big designs in OUTLINE mode doesn't even seem to be faster.