The object you select has to be a valid 2D object. Is it possible you are not using 2D objects?
The functions won't work with Lines, Double Lines, etc. While they will work with Closed Polylines, they will not work with Polylines that are not properly Closed into a 2D object.
TC Pro Platinum 2020, 2019, 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1