Solutions from Synergis: DWF Evolution

9 Jun, 2006 By: Peter Gehring

Learn how to import DWF files into a drawing as a referenced underlay.

We've seen how the DWF (design web format) file format enables architects, engineers and other design professionals to share graphical and non-graphical design data with partners, consultants and clients without having to share the original file in its native format. Designs from multiple CAD platforms can be published as single or multisheet DWF files with information from AutoCAD blocks, Architectural Desktop and Building Systems objects and Revit families. Users can export 2D views with layer information so layer visibility can be modified in the DWF file. Published 3D models can be viewed from any angle and objects and categories can be made transparent, hidden or isolated. These DWF files can be viewed with the free Autodesk DWF Viewer and marked up with Autodesk DWF Composer. The markups can then be imported back into the original DWF with Markup Manager.

The DWF file type continues to evolve and now includes the ability to import DWF files into a DWG file as a referenced underlay that can be clipped, snapped to and graphically adjusted via the Dwfattach command.

Start the command via the Insert pull-down menu, the new Insert toolbar (figure 1), by typing it at the keyboard (DWFATTACH) and attaching from the new external reference manager palette.

Figure 1. You can start the Dwfattach command via the new Insert toolbar or the usual pull-down menus, keyboard input or from the new external reference manager palette.

All of the methods bring up a dialog box similar to the File Open dialog box, but it only shows DWF files. After you select the file and open it, the Attach DWF Underlay dialog box appears.

The options in the DWF Underlay dialog box are very similar to those in the image and external reference attach dialog boxes. You can preset the DWF underlay's insertion point, scale and rotation or input parameters. You can attach the DWF with the same path options that you have with attaching xrefs or images. Because the DWF underlay really is an imported image, there are no options to bind it like an xref. You can unload, reload and detach it. If you attach a DWG as an external reference that includes a DWF underlay, the DWF is included as a nested entity. You can't initially attach DWF underlays as you can with xref overlays, although you can unload them without unloading the parent external reference.

If the DWF file you are selecting is a multisheet DWF, you can select which sheet to insert.

You can only select one sheet at a time. Reuse the command to insert another sheet from the same DWF file or from another. DWFs that are password protected prompt you for the password before attaching them.

If you insert the DWF underlay at a scale of 1, it comes in at the scale at which the DWF was published. The DWF underlay supports all DWG object snaps and also object snap tracking. The ability to snap to DWF object snap points can be toggled on and off by selecting the DWF underlay and selecting the DWF Object Snap option using the right mouse shortcut menu (figures 2a and 2b). You can set the variable at the Command line with the new DWFOSNAP variable. This variable sets that behavior for all DWF underlays in that drawing or any other drawing open in that session. Osnaps tend to work better when you aren't zoomed in too close. It supports running and Osnap overrides.


Figures 2a and 2b. Use the right mouse shortcut menu to turn on the ability to snap to DWF object snap points.

DWF underlays can be clipped (DWFCLIP) just like external references and you can toggle their frame visibility on and off (DWFFRAME). The DWFFRAME variable has three possible settings:
0: The DWF underlay frame is not visible and it is not plotted
1: Displays the DWF underlay frame and allows it to be plotted
2: Displays the DWF underlay frame but keeps it from being plotted.

Graphic characteristics of the underlay such as contrast, monochrome and fade can be set with the Dwfadjust command or in properties (figure 3). Properties give you an additional option to adjust the background colors of the DWF. For more information, go to the Help menu.

The DWF clip command is available at the right mouse shortcut menu. With the DWF selected, you also can set the clipping on or off in Properties as well as turn off the visibility of the entire underlay.

Figure 3. Use the Dwfadjust command or the Properties dialog box to set graphic characteristics.

If you've been using raster images in your drawings, you know that the DWF underlay options are very similar and it's important to remember that you're still really dealing with a referenced image file. When you send a DWG file with a DWF underlay electronically, it's included in the file (figure 4).

Figure 4. When you send a DWG with a DWF underlay it is included in the file.

About the Author: Peter Gehring

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