Kish Avatar Collision Shape Scanner

Second life avatar physics has moved from the classic collision hitbox towards a polygon collision shape which is different depending on avatar size and whether the avatar stands, sits on an object or sits on ground. The polygon collision shape is typically smaller than the avatar hitbox and can sometimes even be located outside the boundaries of the avatar hitbox.

Most viewers can render and visualize the avatar hitboxes for you in realtime, but the collision shapes are not officially defined and to most people they will remain invisible mysteries.
You can however visualize both your avatar hitbox and collision shape using this scanner.