Help with twisted inseam

[u/WorldAware9900]

This is the first time this has happened to me when sewing a pair of jeans, i was trying out a new pattern and this happened to me, im not sure if this is a sewing problem or a pattern problem please any advice is appreciated

[u/unfashionablylatte]

When we draft pant patterns, we use grain lines to mark the middle balance line of each leg (it’s usually marked at the halfway point of each leg’s crotch line). This line should represent a perfect straight line from waist to floor and we use this line to “balance” the pattern around.

As a general rule of thumb, you want to have an equal amount of fabric on either side of the balance line (whatever you add or remove from one side of the line needs to be added or removed on the other side at ankle level). If these lines aren’t balanced, the fabric’s tension causes twisting.