When you use the File Link utility to link a drawing to Autodesk VIZ, the objects have an active link with the original drawing in AutoCAD or Autodesk Architectural Desktop. This means that any edit made to the drawing in AutoCAD or Architectural Desktop can be immediately updated in Autodesk VIZ by reloading the link.

The red flag in the file list means the drawing has been changed in AutoCAD or Architectural Desktop and you should click the Reload button to update the scene in Autodesk VIZ.

The Detach button will cause the drawing file that is linked to Autodesk VIZ to be removed from the scene and removed from the File Link Manager.

Clicking the Bind button will bind the drawing to Autodesk VIZ and sever the active link with AutoCAD or Architectural Desktop.