HGG Community Forums

KhaosAcres explained in this topic : https://www.huntandjump.com/forum/discussion/57552/want-to-gmt-riding-horse-to-warmblood-answered#Item_2

"You want to GMT the bone density.
Riding horses are 1.49 and under
Warmbloods are 1.50 to 2.49
Drafts are 2.50 and up

Changing height to 14.2 and under will make riding ponies, sport ponies and cobs with the appropriate bone densities above"

So height above 14.2 makes riding horses, warmbloods and Drafts, 14.2 and under makes riding ponies, sport ponies and cobs.

If you want to go from a horse to a pony you'll have to gmt the height (as ponies are smaller than horses and vice versa).
If you want to go to a different body type (Riding horse/pony to Warmblood/sport pony or Draft/cob) you'll have to change their bodies, so you'll have to change their bone density.