The free Adobe Reader software that most people already have installed on their computers has a uniquely useful feature that allows you to view and comment on 3D CAD models in 3D space.
1) Save the PDF to your computer
2) Open the .PDF file that has been sent to you for proofing.
3) Click anywhere in the document window to activate the 3D features.
4) You can rotate your model by holding down the left mouse button and moving your cursor. You can zoom in and out by either holding down the right mouse button and moving your cursor, or use the scroll wheel on your mouse. You can pan the model by holding down with the left and right mouse buttons while moving your cursor.
5)You can adjust the Rendering settings and Lighting Settings in the 3D Palate that traditionally shows up in the upper left-hand portion of the document.
6) To Comment on the model, click on the Comment tab in the upper right-hand corner of the document.
7) You can then Comment on the model using either the sticky pop-out window found under the Annotations tab, or by using any of the options under the Drawing Markups tab.
If you are having issues, make sure you have saved the file to a local drive, the 3D will not work in an internet browser. Make sure you have the latest version of Adobe Reader. If you have the latest version and an older version of Acrobat, make sure your computer is not trying to open the file in Acrobat.