About Attaching Files as Underlays

About Attaching Files as Underlays

You can attach a DWF, DWFx, DGN, or PDF file as an underlay to a drawing file. 

You can reference and place underlay files in drawing files the same way as you do raster image files; they are not actually part of the drawing file. Like raster files, the underlay is linked to the drawing file through a path name, which can be changed or removed at any time. However, you cannot bind an underlay to a drawing, and you cannot edit or modify the underlay's content. 

By attaching underlays, you can access files in your drawing without greatly increasing the drawing file size. 
Although underlay files are reproductions of their source drawing, they are not as precise as drawing files, and they will show slight discrepancies in precision. 

Special Considerations

  1. PDF files with more than one page are attached one page at a time, DWF files are attached one sheet at a time, and DGN files are attached one model at a time. 
  2. You can drag underlays directly into the current drawing. 
  3. You can reattach an underlay multiple times, treating it as a block. Each underlay has its own clip boundary and settings for contrast, fade, and monochrome. 
  4. If the underlay file contains layers, you can control how the layers display after attaching the file. 
  5. External references (xrefs) attached to a drawing can include underlays. 
  6. You can view DWF and PDF underlays only in the 2D Wireframe visual style. DGN underlays can be viewed in any visual style. 
  7. Hypertext links from PDF files are converted to text. 
You can copy selected objects from a DGN underlay file into the current drawing with the NCOPY command. 

Password Protected Underlay Files

A file that you attach to a drawing as an underlay can be password protected. DWF, DWFx, and PDF file passwords are case sensitive. 
  1. You cannot attach the file until you have entered the correct password. 
  2. You will be prompted for the underlay file's password each time that you open the drawing. 
  3. If the drawing has several password-protected underlays attached, you will be prompted for multiple passwords. 
The ability to add passwords to AutoCAD files has been removed because this feature does not meet contemporary security standards. You will continue to be able to open password-protected files. 
Powered by AutoCAD® 

    • Related Articles

    • About Underlays

      You can underlay and snap to 2D geometry stored in DWF, DWFx, DGN, and PDF files.  Underlays are similar to attached raster images in that they provide visual content but also support object snapping and clipping. Unlike external references, ...

    • About Unloading Underlay Files

      To improve performance, you can unload underlays from a drawing file.  When you do not need an underlay in the current drawing session, you can improve performance by temporarily unloading it. Unloaded underlays are not displayed or plotted. ...

    • About Detaching Underlay Files

      Underlays that are no longer needed can be detached from a drawing file.  When you detach an underlay, all instances of the underlay are removed from the drawing, and the linking path to the file is removed.  To hide the display of an underlay ...

    • About Modifying the Position, Scale, or Rotation of an Underlay

      You specify an underlay's position, scale, or rotation when you attach an underlay file. You can also modify these settings later during the drafting process.  By default, the insertion point of a file is 0, 0, 0, its scale factor is 1, and its ...

    • About Comparing Differences Between Drawings in AutoCAD

      Compare the current drawing either to a different drawing or compare it to a previous version of your drawing as maintained on a supported cloud account. As your design progresses, it becomes more difficult to remember what was changed from one ...

    • Recent Articles

    • Toolbox Release Notes | Build 24.1.0416.641

      The following release notes apply to Toolbox build 24.1.0416.641. Maestro Toolfile Fix There was an issue with Maestro SCM Toolfiles reportedly experienced by some users, wherein the labels output by autolabeling would be in incorrect positions, an ...

    • Toolbox Release Notes | Build 24.1.0409.641

      The following release notes apply to Toolbox build 24.1.0409.641 Saw Delimited Processing Station Figure 1: The Saw Delimited option in a custom processing station. New options have been added to saw processing stations to allow for control over data ...

    • Toolbox Release Notes | Build 24.1.0328.641

      The following release notes apply to Toolbox Build 24.1.0328.641 Fillet Token Fixes Issues were discovered in the use of fillet tokens on products that also had the IRIB setting enabled: Some users processed work orders with rounded parts, which ...

    • Microvellum Foundation Library Release Notes | Build 24.0322

      Additions Added the Master Angled Ends Cabinet. Added a Global prompt, "Hinge Plate Offset From Front" for easier control. Added “Double Division” option to Horizontal Designer Cabinets, 3 Door Cabinets, and other similar products. Added a new ...

    • Common Floating License Connectivity Issues

      This document lists common issues reported by users regarding the topic of Microvellum’s Floating License Activation (FLA) and the connectivity required for FLA to function. Firewall Blocking Activation of Floating License Some users have had an ...