Actually my verbose explanation isn't actually that long of a method. It's just a single step. and that's just X coordinate mirroring. That is if a line splits you in half that is perpendicular to both the direction you are facing and the ground you stand. Your left hand would be your right hand and you right would be you left, continuing to everything. This effect also flips the orientation of these flipped part so after all the flipping only the distinct markers will have moved "visually." The marks could be birthmarks, scars, you dominate hand, etc. Basically It's the same effect you would get by looking at yourself in a single flat mirror.

Short version: single step done just before storing model to memory for use.