Autodesk supplies some of our DWF partners in the commercial printing industry with technology that allows DWF files to be printed by reprographic software. This technology is referred to as the DWF Printer Development Kit (PDK).
A reprographic customer recently reported two problems:
- In printouts received from his reprographer, dot-based fill patterns were printed too dark. Printing to same device directly from the DWG using AutoCAD yielded the expected results. Printing to the same device directly from the DWF using the Autodesk DWF Viewer yielded expected results.
- Some sheets contained in a DWF file were printed as blank pages.
PDK Software Developer, Ben Cochran, developed fixes for these issues:
- AutoCAD often draws dots as lines where the starting point is the same as the ending point. In the DWF PDK, the line attributes of short lines (length 0) were not being rendered correctly. The correct weight and cap style were not being applied. In some cases this produced fill patterns that did not render correctly.
- In some uncommon cases AutoCAD 2007 produced DWF packages with multiple sheets whose sheet names differed only by case, e.g., Sheet ABC and Sheet abc. This resulted in a sheet name collision and some of the sheets could not be rendered. This was only a problem with some DWF large DWF files published from AutoCAD 2007. The DWF PDK was not handling sheet names in a case sensitive way.
PDK 18.104.22.168 includes Ben's two corrections. PDK 22.214.171.124 is being integrated into updates for PLP PlotWorks and KIP Powerprint. Océ Repro Desk Client Tools 1.6.4.002 uses DWF PDK 126.96.36.199. This application does not yet benefit from these corrections.
In case you are wondering why there was a difference between DWG printouts, DWF printouts, and the printouts from the reprographer (from the PDK), the goal is to get the same printing from all of the following use cases:
- AutoCAD/Revit/Inventor/etc. printing directly to a printer via the printer’s Windows print driver.
- AutoCAD/Revit/Inventor/etc. printing to DWF and then using the Autodesk DWF Viewer to print the DWF to a physical printer’s Windows print driver.
- AutoCAD/Revit/Inventor/etc. printing to DWF and then using the PDK to render an image which is then printed to a physical printer.
Note that in each case if the user has objects (lines, etc.) with “zero weight” then AutoCAD will send the zero-weight object to the output as an object with a weight of 1 pixel. As you know physical printers can’t print lines with a single pixel.
- In case 1 above, the printer manufacturer’s Windows printer driver will automatically thicken 1 pixel weights to be something thicker that is printable. This is a device dependent setting since it is applied by the print driver and NOT by AutoCAD/Revit/Inventor/etc.
- In case 2 above, the DWF will receive the 1 pixel weight from AutoCAD and will store that 1 pixel weight in the DWF file. The DWF Viewer in turn will print to the Windows print driver where the device manufacturer’s code will again auto-thicken the 1 pixel weight to a printable weight that is device specific. This thickening done by the print driver (not by the DWF Viewer) is exactly the same thickening that occurs in case #1 and thus the output from the DWF is the same as the output from AutoCAD.
- In case 3, there is no device manufacturer’s driver involved. Thus the thickening of very thin geometry has to happen in the DWF PDK. The PDK allows an application, such as PLP PlotWorks, to specify how much you want the PDK to thicken so that the output can match what a device manufacturer would have done in their device specific driver. Applications should set your the default PDK thickening value to match the device you are attached to. There is no reason for users to play with this setting.
Although DWF allows you to go beyond the paper, getting the design data on the paper is also important. Autodesk continues to support the reprographics industry in the printing of DWF files.