BiasThe diagonal line of the fabric at 45 degrees to the lengthwise and crosswise grains. A garment is said to be “cut on the bias” when the warp and weft threads are at 45 degrees to the major seam lines. The bias line has the most stretch, and fabrics cut on the bias drape well.
Image 1Showing the lengthwise, crosswise and bias grain on a piece of fabric.
Image 2A garment is said to be “cut on the bias” when the warp and weft threads are at 45 degree to the major seam lines. In this image the Major seam line for these two skirts is the Center Front. In the skirt (overlaid) to the left, the CF is aligned with the lengthwise grain – this is the more common way to lay the pattern on the grainline to cut out a skirt. On the right hand side is a skirt laid with the CF on the bias. It may be hard to visualize the grainline on both sides of this skirt.. so have a look at the next image.
Image 3In this image, instead of using a half-skirt pattern piece placed on the fold, a full skirt pattern has been placed with the CF on the bias. This is the same as using half and placing it on the bias – it is just easier to see how the grainline runs through both sides of the skirt.
Image 4On the left is how the grainline would be placed on the pattern piece, and on the right is how the grainline would be working in the skirt. As the Lengthwise grainlines are “strong”, they would would want to hang vertically and would pull down, giving more scalloped edge to the hem (see next image) than a skirt with the CF on the straight grain.
Image 5This is a dress with the skirt cut on the bias.