Adobe Font Metrics file is a file in the special format described here:
This file contains the metric information about the font but not the font itself. In particular, it contains widths of all characters and bounding boxes for all glyphs. AFM files can be used to estimate the space that the string in that font will occupy as well as to determine if the string fits into a certain region of the document.
Altsoft Font Type Master allows you to generate AFM file for all supported types of fonts except Multiple Master fonts which do not have single set of metrics. To do this you may either press the (Generate AFM) button on the toolbar or choose 'Generate AFM File' from 'Tools' menu:
After that a window opens and you are asked to choose a file for saving AFM information in it. Note that at present the kerning information is not retrieved.