How to tell the oblique direction of the twill

Update:21 Sep 2018
Summary:

Twill fabric: The twill arrangement is divided into sin […]

Twill fabric: The twill arrangement is divided into single-sided twill and double-sided twill. The texture of the single-sided twill is clearly visible on the front side, and the discord is not clear. In addition, in the aspect of texture skew, the front texture of the single-yarn fabric is skewed from the upper left to the lower right, and the texture of the half-line fabric or the full-line fabric is skewed from the lower left to the upper right. The double-sided twill is not exactly the same as the texture. But the diagonal is opposite.
The specific methods are:
1. If there is a cloth edge, look at the shape of the pinhole (which is left when you pack it)
2, look at the appearance of the cloth, usually the cloth surface is brighter, the texture is clear for the front
3, if it is sanding, grabbing type, usually the condition of the matte surface, the scratching surface is positive
4, the usual twill cloth is right oblique is positive, but the line card is left oblique is positive.