I try to ensure that any figures in my renders do not hover off the floor but it can be difficult to get the placement right for the reason given. The way I work when I have problems is to place a camera beneath the ground and drop the figure to the floor, if there is a problem with the footware the soles, heels or both will appear. I then lift the figure until the offending parts disappear.

 

 

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.