Laptop keycaps for Asus UX31A
This is more off-topic as an answer, but serves as a possible solution.
Replacementlaptopkeys.com is a resource that appears to have keycaps for the model you've noted.
https://www.replacementlaptopkeys.com/asus-zenbook-ux31a-db71-laptop-keys-replacement-dark-brown-black/
At seven dollars a key, it's going to be less expensive than 3D printing to accomplish your objective.
If you owned a 3D printer, it would not be less expensive to purchase, but the work involved would increase your cost to have such keys commissioned. As a 3D printed object, the strength is going to be less than a keycap purchased from the linked site.