I wondered if anyone might know . . . . My mum has asked me to design and make a new cover for the seat of her piano cushion and I know the dimensions that needs to be in cms. I'm using the Jane Greenoff Cross stitch designer software but I don't know how to translate the size of everything I'm seeing on the screen into cms on the fabric. I plan to use 14 count Aida (I think). Does anyone understnd what I mean? Can anyone help?