These bisections are to illustrate the postural correction achieved at the knee, the ankle and the forefoot.
We decided to use the AP midline through the center of the knee and lateral aspect of the big toe.
Many orthotic manufacturers illustrate their orthotic achieve these postural improvements, however this is most often not the case.
For more information on these postural changes a MASS4D™ orthotic achieves please watch this clip. MASS4D on Foot Biomechanics