Mult. finish diameters controls the use of multiple finishing tools and is specified as a list of diameters separated by commas. If you want FeatureCAM to select the tool to use for the last pass, set the last Tool Diameter to 0.
Your Mult. finish diameter list should work its way gradually down to the desired finish tool. One way is to let the system pick the tooling initially, then set up your diameter list to work gradually toward the last value. If the system recommends a 0.125 inch endmill, set your Tool Diameter attribute to “1.0, 0.5, 0”.
By default, FeatureCAM creates one finish pass for all of the milled features. If you use multiple finishing tools, FeatureCAM cuts all the parts of a feature that it is capable of cutting with the larger tool, and cuts only the remaining portions of the feature with the smaller tool. You do not have to manually create these separate regions. FeatureCAM automatically calculates them for you.
See also Finish pass z increment.