Roblox's body scaling is a feature released on November 16, 2016. It's only available for R15, and allows you to scale your avatar.
Options[]
Height[]
Height allows you to change your height. It's capped from 90% to 105%. You can scale it over the cap with Studio.
Width[]
Width is an option that allows to change the width and depth. These two are usually merged into one but you can modify them separately in Studio. It's capped at 70% to 100%.
Head[]
Head is an option that allows to change the size of your avatar's head. You can also modify it in Studio. It's capped from 95% to 100%.
Body Type[]
Body Type is an option that allows to change the body type, It makes the avatar look taller and slender. It's capped from 0% to 100%. You cannot modify it over the cap in studio.
This is the foundation of Rthro's scaling.
Proportions[]
Proportions, as the name says, is an option that allows to change the proportions. It makes the proportions seem narrower, more closer to the original default size.
Criticism[]
The body type was rumored by many players to be a sign of Rthro's (then called Anthro) release.