## Region where all contact forces are sampled

*OUTPUT_CONTACT_FORCE is a new command for measuring contact forces. All contact forces in a user-defined region are sampled and the resultant is output to the ASCII file contact_force.out. This is a convenient tool for extraction of forces against individual parts, without having to subdivide the contact definitions into multiple *CONTACT commands.

### Example

A simple example where we extract the contact forces against a projectile penetrating a concrete target:

#
# --- One contact definition for the complete model ---
#
*CONTACT
"all to all"
ALL, 0, ALL, 0
#
# --- Measure contact forces against Projectile (Part 3) ---
#
*OUTPUT_CONTACT_FORCE
"Projectile"
1, P, 3