By default faces (or ‘flexes’) in the Source engine are clamped to sane levels. This makes sense in the real world, but makes slightly less sense in GMod where we don’t always want people’s faces to stay on the front of their heads.
So I found the clamping code today and disabled it. Now GMod’s faceposer can totally wreck faces.. like this.
But if you take your time and are careful you can generate new extreme faces that haven’t been possible in GMod before..