Pattern direction can be important for upholstering. An upholstery fabric can be non-directional, railroaded or not railroaded. A non-directional material does not have a defined way that the fabric should be applied. Railroaded patterns are great because you do not need a seam every 54 inches. You would need a seam every 54 inches (the width) for not railroaded fabrics, but this is not always a big deal. Not railroaded patterns are also good for drapery. Below are examples of railroaded and not railroaded patterns:
The pattern (smiley faces) is running across the roll. The pattern is parallel to the length of the fabrics. You will not need a seam every 54 inches.
The pattern (smiley faces) is running up the roll. The pattern is parallel to the width of the fabric. You may need a seam, but it isn’t always a big deal.