This is the diameter of the tool that was used to previously cut the part.   This parameter applies to all remachining methods.

The amount to cut past the boundary. It is specified as a percentage of the tool diameter. It is usually a good idea to overcut a little to ensure complete coverage.

This setting is also involved in specifying the region to be cut by overstating the previous tool diameter.  This explains why increaseing the overcut percentage can expand the regions that are remachined.  This parameter does not apply to corner remachining.  It only applies to parallel, Z-level and 3D spiral remachining.  

This parameter does not apply to corner remachining.  It only applies to parallel, Z-level and 3D spiral remachining.  

This setting can be used to filter out regions that have a minimal amount of rest material left by the "previous" tool. The default is 0 which means it will try to cut anywhere the previous tool had a double contact with the part surfaces, including a fillet of the same size as the previous tool (assuming overcut is set to 0 also). If the minimum rest material is set to a positive number, the remachining will only include tool paths that remove rest material that is greater than this depth. It's main use is to handle the case where you have some part fillets exactly the size of the previous tool and some that are smaller. If you do not want to remachining the part fillets that are exactly the size of the previous tool you can set "overcut" to 0 and "minimum rest material" to 1 or 2 times the machining tolerance to make sure the previous tool radius sized fillets are not remachined.

The part has some fillets that are 10 mm radius and some smaller fillets. Remachining with "previous" tool diameter of 20 mm and the default overcut of 5% remachines all the fillets.

 

If we set overcut % to 0 to avoid cutting the 10 mm fillets we may get some unwanted tool paths, depending on the machining tolerance and the accuracy of the part model. Here the machining tolerance is set to .01 mm and we have some unwanted tool paths.

Setting the "minimum rest material" to twice the tolerance (a rough rule of thumb, .02 mm in this case) eliminates these extra tool paths.

Another use for the new "minimum rest material" is to eliminate "noise" from the remachining tool paths due to inaccuracies in the part surfaces, non-solid models, poor tolerances, etc.