Partially constrains a point in the template. The vector offset dictates that the child point has two parent points and is projected onto the vector defined by the two parent. If the offset is not 0, then the child point maintains a perpendicular offset from the parent vector at the specified offset value. Negative values indicate an offset to the left of the vector defined by the parent points. Positive values indicate an offset to the right. For more details on constraints, see Create Template Overview.