The Purpose of The Displacement Exporter

From ZBrush Info

This concept of alpha maps for displacement or normal mapping is simple, but there are various technical details that need to be handled correctly when transferring alphas between different packages. Taking care of all of these details by hand is time-consuming and prone to error. ZBrush’s Alpha Displacement Exporter (DE) allows you to set just once the options you need to correctly export alphas to your favorite program. ZBrush will remember and apply those options from that point on.

Before getting into the technical details of transferring alpha displacements between applications, there are two features of the DE that may allow you to use it with little or no configuration on your part.These are described in the section on Presets and Quick Codes.

Presets

The DE ships with many predefined configurations, with names like D32 or PN16. One of these is likely to be appropriate for transferring a ZBrush alpha to your target program.

Quick Codes

The DE also provides a feature to enable you to quickly enter configurations developed by other users. Quick Codes are strings that define a full set of export configuration values. If none of the predefined DE configurations are appropriate for your needs, check ZBrushCentral1; you may find a quick code someone else has developed to transfer alphas to your application of interest. In that case, entering that quick code will give you the settings you need, and you will not need to worry about the other options in the DE interface.