They are made from rigid materials, metal, plastic, carbon-type materials, and can be covered or not covered. But they must be made accurately. There are several ways to construct an orthotic. One is to take a plaster impression of the foot. The newer, more advanced way is to take an optical impression of the foot.
Some people use a foam based impression.
But in any event the form of the foot must be captured accurately and the form is then sent to an orthotic laboratory, such as Palmetto Pedorthic Center, to be transferred into a mold of the patient's foot. Corrections are made to that mold and an orthotic is made from that corrected mold. Orthotics are used for many conditions, from childhood to adulthood. In the very active age group, such as runners or sports related activities, specially constructed orthotics are accommodated to the specific sporting event. Most professional athletes and weekend athletes use orthotics to help increase their performance.