When a drawing is attached to current drawing as external reference, it will be linked to the drawing, any changes to the referenced drawing may affect the external reference in current drawing.
External references are inserted into the drawing as block definitions and used as single objects, But you should distinguish the external references and blocks.
An xref can be attached to various drawing simultaneously. In the same way, you can attach multiple xrefs to the same drawing using full path or relative path that are partly defined. Even without saving path.
You should notice that, xref must be object created in model space, when inserting xrefs, you can specify the insertion scale, position and rotation angle.
When you attach an external reference, its layers, linetypes, text styles, and other elements are not added to the current drawing. Rather, these elements are also linked from the referenced file.
There are two ways you can attach an external reference:
An attachment is an inserted drawing that contains a link to the original file. Attachments can themselves contain other, nested reference files. When you attach an external reference, any nested references contained in the file also appear in the current drawing.
An overlay is also an inserted drawing that contains a link to the original file. Overlays allow you to lay a drawing on top of another drawing, similar to the way you work manually with transparencies. When a drawing that contains overlaid external references is itself attached or overlaid as an external reference in another drawing,the overlays do not appear as part of the external reference. Use overlaying when you want to see reference geometry in a drawing but you do not need to include that geometry in drawings that will be used by others (nested external references).
To attach an external reference
Choose Insert > Xref Manager.
Specify the drawing file to attach as an external reference, and then click Open.
In Reference Type, choose how you want to insert the drawing:
Attachment – inserts a copy of the drawing and includes any other drawings that are exter nally referenced within the referenced drawing.
Overlay – lays a copy of a drawing over your original drawing; it does not include any nested external references from the externally referenced drawing.
Make any additional selections.
If you marked Specify On Screen for any items, follow the prompts to attach the external reference.
Command line XREF
Notification of Attached Xrefs
After inserting external references into the drawing, a xref icon displays at the lower right corner of status bar on ZWCAD application window. Click this icon shown below to display External Reference manager:
If the original drawing to which the xref links has been changed and needs to reload, an exclamation mark appears on the xref icon.
Attach External References
You can use the following methods to attach xrefs into a drawing:
Attach xrefs to current drawing using XATTACH command.
Starts xref manager using XREF command, and select xref to attached to the current drawing.
Select xref drawing to insert into the drawing from DesignCenter, and right click the drawing to select Attach as xref.
Viewing the list of external references
You can view a list of the external references that are linked to the current drawing two different ways using the Xref Manager:
List View displays the external references in a list, which allows you to sort the list of references by name, status, size, type, date, or saved path.
Tree View displays a hierarchical representation of the external references and the relationships between them. The tree view shows the level of nesting relationships of the attached external references.
To view a list of external references
Choose Insert > Xref Manager.
Click List View or Tree View.
Command line XREF
Visibility, Color, and Linetype
You can control visibility, color, linetype and other properties by setting the layer on which the xref locates. You can also assign these changes as temporary or permanant.
If the system variable VISRETAIN is set to 0, layer table stores in the xref has superiority, modifications based on layer made for xref of the current drawing are only available for current command. These changes will not saved along with the drawing. When restart the drawing, layer table will be reloaded and changes are still remained in current drawing.
If the system variable VISRETAIN is set to 1, modifications based on layer made for xref of the current drawing has superiority.Layer settings will be saved in layer table of current drawing. And in accordance with current tasks.
Xref Clipping Boundaries
You can control whether to display clipping boundary of xref through setting system variable XCLIPFRAME.
BASE: Sets the insertion base point for the current drawing
REFCLOSE: Saves back or discards changes made during in-place editing of a reference (an xref or a block)
REFEDIT: Selects a reference for editing
REFSET: Adds or removes objects from a working set during in-place editing of a reference (an xref or a block)
RENAME: Changes the names of objects
XATTACH: Attaches an external reference to the current drawing
XCLIP: Defines an xref or block clipping boundary and sets the front or back clipping planes
XREF: Controls external references to drawing files
System Variables Reference
BINDTYPE: Controls how xref names are handled when binding xrefs or editing xrefs in place
INDEXCTL: Controls whether layer and spatial indexes are created and saved in drawing files
INSBASE: Stores the insertion base point set by BASE, which gets expressed as a UCS coordinate for the current space
PROJECTNAME: Assigns a project name to the current drawing
VISRETAIN: Controls the visibility, color, linetype, lineweight, and plot styles of xref-dependent layers
XCLIPFRAME: Controls the visibility of xref clipping boundaries
XEDIT: Controls whether the current drawing can be edited in-place when being referenced by another drawing
XLOADCTL: Turns xref demand loading on and off and controls whether it opens the original drawing or a copy
XLOADPATH: Creates a path for storing temporary copies of demand-loaded xref files
XREFNOTIFY: Controls the notification for changed or missing xrefs