★★★What is DWG external reference used for in ZWCAD

Issue:

What is the DWG drawing attached as an external reference used for?

External Reference Concepts:

• DWG external reference is used to attach a DWG file to one or more drawing files in the form of a reference. Each modification of the external reference will be updated in the drawing files which refers to it in time. Use the XREF command to reload the external reference to update the attached Xref drawing to the latest version.
• As shown in the figure below, the current file "Room Plan" attaches "Room" as an external reference. As a result, the current drawing has the Room attached to the Room Plan to complete the floor plan.

• There is a substantial difference between a DWG external reference and a block. Once a user inserts a block, the block will be permanently inserted into the current drawing and will not be updated with the change of the original drawing. The information of the external reference file is not directly transferred to the current main drawing file, but only records the referenced relationship and path, and establishes a reference relationship with the current file.
• A drawing file can be attached to multiple drawings at the same time as an external reference. Conversely, multiple drawings can be attached to a single drawing as reference drawings.

The Use of External Reference:

• Standardization: Some contents in the drawing are unchanged or uniformly changed. For example, the frame of all drawings is the same, which can be used as a block, but if an external reference is applied, the frame of the drawing will be updated automatically if the frame is modified.
• Collaboration: decompose the workload into several drawing files, create only the main drawing file, assign different design files to different designers, and then assemble the drawing files together by external references.
• To reduce the file size: attach the entire DWG drawing file to the current drawing as a reference. The attached Xrefs are linked to another drawing, which is not actually inserted, thus, it does not increase the drawing file size.

XREF Command:

• Input command XREF to open the External Reference panel to manage attached reference drawings in the current file.
• Permanently binds the attached reference drawings into the current drawing when the project is completed and ready to be archived.
  (Note: ZWCAD2021 and later versions can use the XREF command to manage DWG, DWF, DGN, PDF, and Image references. Only DWG format files can be bound.)