The T-1000, portrayed in human form by actor Robert Patrick, was a sharp-shifting "liquid metal" cybernetic assassin. ILM had to seamlessly integrate the live-action effects with the work of Stan Winston's team to pull off the effect that director James Cameron was going for – ultimate photorealism. ILM developed a new technology called "Make-sticky," which allows for textures applied to CG geometry to maintain their position despite having objects pass through them -- such as the iron security gate in the psych ward where Sarah Connor was being held.
A cyborg, identical to the one who failed to kill Sarah Connor, must now protect her young son, John Connor, from a more advanced cyborg, made out of liquid metal.
Terminator 2 was arguably the most groundbreaking visual effects film of all time in terms of proving the promise of digital effects.
To create the shape-shifting liquid metal T-1000 and slip him into live-action shots ILM had to wrangle a ton of tools into production-worthy form, so they completely revamped their complex rendering tools, compositing software and painting tools. To anchor the character in the frames, Visual Effects Supervisor Dennis Muren made sure the character had the correct reflection maps as the liquid metal distorted.
A version of Photoshop, developed by ILM’s John Knoll and his brother and first released on a Macintosh in 1990, helped artists repair frames that showed torn geometry.
It was ILM’s first film that used a fully digital process – a digital scanner that ILM had developed with Kodak, a digital film recorder, and Photoshop. And, it was the first film that didn’t simply include CG effects; it relied on them.