Drawing diagrams on cuts through panels consists of the traces of the cutting through a user defined plane and the shell elements creating a panel. On the trace a diagram is drawn. Defining the plane by itself does not cause doubts, the diagram orientation in space is not obvious and involves defining the normal in respect to a cut plane.
Each plane divides the space into two semi-spaces. One semi-space is considered positive. This division is aimed to orientate a cut plane by defining a vector normal to the cut plane. This determines the positive side of the plane and the local Z axis. Defining the normal vector depends on a definition of the cut plane chosen by a user. With the exception of two cases, the normal vector is a vector product of two vectors. Definition of each of them depends on a plane definition.
If diagrams on cuts are to be perpendicular to the cut plane, then the above-defined normal vector determines the diagram axis unambiguously. Positive values are designated according to the normal vector orientation, whereas negative values are indicated on the opposite side. In this case, the positive axis orientation depends solely on the normal line orientation with respect to the plane.
If diagrams are to be positioned in a cut plane, then a vector product of cut trace and normal vector to the cut plane are calculated. The orientation of this vector is determined in such a manner so that the vector's largest coordinate is always positive. The defined vector indicates the diagram axis. Take note that each of the cut segments may have different directions depending on the vector of a cut trace. However, for the same trace originated from cutting with planes whose normal lines show different orientations, the positive axis orientation will be the same.