I visited Kerner Optical some years ago, which did that kind of work. They were originally a part of Lucasfilm, and were spun off to sink or swim on their own. They sank. Here's some of those guys at work, on the first "Pirates of the Caribbean" film.[1] They were 10-20 year veterans of physical effects. Someone who'd been there five years was the new guy.
Tippett Studios was one of the big model work studios. Phil Tippett saw the writing on the wall when Jurassic Park went digital. The original plan for Jurassic Park was to use models of various sizes. Now Tippett is a digital effects house.
Not that being a digital effects house means job security. That's become a grind of a business, outsourced and offshored.
Minor clarification, Kerner Optical was the unofficial codename for ILM, the model shop that build physical props was spun off and they decided to name themselves Kerner Optical.
In the original Jurassic Park, dinosaurs moving in the open are full CG.[1] Close-ups where the actors were directly interacting with the dinosaurs were model work. That was the first major film with photorealistic CG creatures.
It's still difficult to do close interaction between humans and CG-animated characters, although, with enough money and a huge team, it can be done. See "Guardians of the Galaxy" to see that done very well.
Tippett Studios was one of the big model work studios. Phil Tippett saw the writing on the wall when Jurassic Park went digital. The original plan for Jurassic Park was to use models of various sizes. Now Tippett is a digital effects house.
Not that being a digital effects house means job security. That's become a grind of a business, outsourced and offshored.
[1] https://www.youtube.com/watch?v=urvcYSpiwQA