This is a sketching tool I developed for a competition at the office. We needed to quickly and easily evaluate the fesibility of a given plot through sketching various volumes. We looked at the following criteria: BTA, LOA, Even Facade Division and Facade Area.
With this tool it is possible for the designer to manually sketch in Rhino with Grasshopper running in the background doing all the bulk calculations and giving live feedback of the sketched volumes. The pros of manual workflows like this compared to generated ones is that you as a designer are always in full control of the shaping and carving. The tool allows you to easily add and substract from the volume.
Sketching buildings and getting instant feedback on metrics is now much faster and it still allows the architect to be in full control of the design. The computer is merely there to assist with feedback and suggestions. It is in the end up to the designer to choose which design is most pleasing and "best" performing.