Find. Select the PDF underlay to adjust. On the Enter PDF Underlay Options menu, select one of the following Select Fade and enter a fade value. Select Contrast and enter a contrast value. Select Monochrome and set monochrome to Yes or No. The appearance of the PDF underlay is updated after you enter the new value and the command is completed. . Make PDF underlay unselectable Apr 1, 2016 Come to think, it would be cool if AutoCAD had that capability built- in , to be able to make objects or layers unselectable, another one that. How to explode pdf underlay in autocad. Block cannot be exploded in AutoCAD or Causes Beginning with AutoCAD &174; 2006, the Allow Exploding option was added to the Block Definition dialog box. You plotted from AutoCAD to PDF , and the file size is too large. You need to reduce your PDF file size. Cause. PDFs created from AutoCAD are a vector-based graphic file. The Forster exclusive Co-Ax Case & Cartridge Inspector provides you with the ability to ensure uniformity by measuring three critical dimensions neck wall thickness, case neck concentricity, and bullet runout . Measurements are in increments of one-thousandth of.