Probably a bit of both. There is a built-in stl import that needs no other widgets. Once in the result is standard geometry not different from others except how the faces are laid out as the stl is a stack of parallel shapes and I can see possible problems there but it may get fixed in the import.
More of a problem is the grayscale material as where the lightest and darkest parts are is very orientation dependent, and then the lowest points will be hidden in back giving you fewer shades of gray to play with.
I made this building it in Blender going first to Wood Workshop, and then Gimp as I could not get the grain to go side to side. Straight out of Gimp the verticals of the grain overwhelmed the low spots but Blender fixed that.