Are there scientific and technological limitations in 3th density?

[anagogy]

I've read that Atlantean technology could transform an animal face into a human face, albeit with much pain to the animal. They used crystals and the power of thought.

I wonder why they would want to do that?

To create a servant class of beings (slaves) who had some of the dexterity and intelligence of humans, but not enough to escape their situation. So, they would use their technology to blend some human characteristics with 2nd density characteristics.