As with #RecMin (classic version) and with the new PRO version, you will be able to build 3D solids from geological interpretation polygons, with almost nothing to envy of commercial software. You can also import and export geological solids from RecMin to other mining software. You can calculate the volume of each solid with various RecMin methods and perform block modeling and grade estimation. So, if your project needs to do this and you don't have enough budget to buy some commercial mining software package, try to do it all with RecMin, it is free and also has an English interface. Contains a small online help if you press the F1 key