Adobe ACROBAT 3D Manual page 514

Using Discard Objects settings
The Discard Objects panel of the PDF Optimizer lets you specify objects to remove from
the Adobe PDF document and lets you convert smooth lines to curves. The level of
compatibility that you choose from the Make Compatible With menu determines the
objects that you discard. Objects that can be discarded include both objects created in
Acrobat and objects created in other applications. Selecting an object removes all
occurrences of that object within the PDF document.
In the Discard Objects area, you can select from these and other options:
Discard All Alternate Images
Removes all versions of an image except the one destined for on-screen viewing. Some
PDF documents include multiple versions of the same image for different purposes, such
as low-resolution on-screen viewing and high-resolution printing.
Discard Embedded Thumbnails
Removes embedded page thumbnails. This is useful for large documents that can take a
long time to draw page thumbnails after you select the Pages tab.
Discard Private Data Of Other Applications
Strips information from a PDF document that is useful only to the application that created
the document. This does not affect the functionality of the PDF document, but it does
decrease the file size.
Discard Document Structure
Removes tags from the document, which also removes the accessibility and reflow
capabilities for the text.
Discard Hidden Layer Content And Flatten Visible Layers
Decreases file size. The optimized document looks like the original PDF document but
does not contain layer information.
Convert Smooth Lines To Curves
Reduces the number of control points used to build curves in CAD drawings, which
results in smaller PDF files and faster on-screen rendering.
Detect And Merge Image Fragments
Looks for images that are fragmented into thin slices and tries to merge the slices into one
image.