Using prosthetic appliances we can give three dimensons in the face or the body of an actor.
This appliances can be made by foams or silicones depending each work.
Any material that we glue on the skin reacts with the actor's expressions giving more realism to the character.
From scars and wounds or little appliances like noses or cheeks to full head multipieces appliances or full body suits to create any kind of character also sometimes including animatronic movements in it to reinforce the actor's performance.