In SOLIDWORKS Sheet Metal, the bounding box algorithm finds the smallest area in which to enclose the flat pattern for the part. At times, the direction of the bounding box is not very effective. When this occurs, you can specify the bounding box in any direction by using a sketch or an edge in the Grain Direction option in the FeatureManager.
1. In the FeatureManager design tree, expand Flat-Pattern folder.
2. Right click at Flat-Pattern and choose Edit Feature.
3. Click at the grain direction box and select the proper edge direction.
4. The flat-pattern direction will change accordingly.