Black Lines/Space1 over parts

I was building a simple Minecraft themed stage, just for fun and testing until i saw that some blocks have this little black lines over them, it isn’t a big issue but aesthetically is pretty annoying

How could i fix this?

Those black lines are either part of the texture themselves or tiny misalignments in the parts. I suggest keeping the parts in nothing more than three significant figures (in scale) or the positioning with all the decimals get really messy. Also, check the positions of the parts to make sure they don’t have co-ordinates like “1823.82784638” or something.