I am very enamored with the iconic "impossible mirror" shot in Robert Zemeckis' "Contact" instead, which used subtle CGI to brilliant effect to innovate over the practical bag of tricks. It's my single favorite effects shot in movies: https://youtu.be/avRdYf78kLk (from 1:10 for the impatient)
Almost certainly not; that's the point.
https://www.youtube.com/watch?v=ULxw4UDY5g8 (up until 0:35)
2. The original Birds did not have that music. I cannot believe how classic media remasters completely ruin the tone of the originals. From Star Wars, to Rust in Peace, to Birds now.
How come the camera is not in the way at that point? Did it move backwards to the closed door? The answer is quite interesting. Let me know if you'd like me to spoiler it for you.
I always assumed that the "big room" was to avoid the culling algorithms / potentially-visible-set tripping over the mirror.
In general, lots of things in games require re-rendering the scene multiple times per frame, so game engines are really, really good at this. Shadows, projections, transparency / translucency, motion/depth blur, indirect lighting, deferred lighting, even things like hit testing (though for dependency + latency reasons that's a prime candidate for offloading to the CPU). Anything that requires less visual fidelity will have its performance tuned accordingly: fewer pixels, simpler shaders, lower LOD geometry, lower framerates. Nobody will notice if the fuzzy bounce lights are calculated once every five frames and blended.
Ray tracing is conceptually simpler but (so far) slower at any given level of cleverness -- you'll often hear that it has asymptotic benefits, but those same benefits can be pulled out of rasterizers with effort comparable to what is required to make the raytracing practical.
Here is a writeup of the passes you might expect to see in a modern engine: https://zhangdoa.com/posts/rendering-analysis-cyberpunk-2077
Here's an overview of a modern geometry pipeline: https://www.youtube.com/watch?v=eviSykqSUUw
Tradeoffs, tradeoffs, everywhere.
That said, it often makes sense to drop some of the decorative flourishes used on the primary instance of the model due to distance, or use a different level of detail. There’s really no great way to get around needing to tell the GPU to render the triangles twice (short of rendering the view to an intermediate buffer and using that, which is still twice…)
Without using this technique you'd have the camera in shot.
The other identical twin thing I remember was an episode of Buffy the Vampire Slayer where Xander was split into two, one of him all his strengths and the other all his weaknesses. Nicholas Brendon's twin brother was used in the scenes where there were two Xanders in one shot.
To the impatient: The meaning of this shot depends on the first 1:09 minutes.
This is what I remember from T2 director's cut: https://www.youtube.com/watch?v=yiBHj8Xs4sg (at 0:21).
When I saw the theatrical cut it always confused me how John could tell who was the T1000. And it also annoyed me that Arnie shot the frozen T1000, seemingly only speeding up his thawing.
In the director's cut you see that T1000 is actually damaged, but not damaged like a non-liquid robot would be. It's not losing mobility (control) of an arm, but instead losing control of its morphing functions.
It's complete genius that was (almost[1]) entirely cut from the theatrical cut. It's ridiculous that the edit it out.
[1] There's exactly one "flicker" of T1000 metalliness in the theatrical cut. A small remnant of a genius idea.
I can't find the "making of" video where they tell how they did this, but here is the cut scene: https://youtu.be/tZNE637BeEI
In scenes where you see Arnie's face in the mirror at the same time as his head being operated on, it's not a mirror, and one of the two Sarah's is not Linda Hamilton (whoever's face is shown less clearly).
Edit: lots of hits on Google saying this is how they did it, but I cannot find a single authoritative reference, like a making of video or someone involved in the production saying so.
Got it, yeah that was a good use of her.
I also really like the scene where John tries to teach him to smile, but at least there they have the excuse that it's a minute or two in length.
Certain other scenes, like Kyle's visit and the extra nuclear nightmare scene, I think the movie is better without.
The actor playing John Connor looks ridiculous. Linda Hamilton in aged makeup looks silly. The whole scene looks corny.
And it defeats the "no future" vibe that worked so well in the first Terminator movie.
"There's a storm coming."
The same technique of using an extended set to fake a mirror was frequently used on Quantum Leap.
They are in front of a mirror. They wanted to actually use Arnie in the reflection to show his face; they wanted a dummy for the head closest to the camera, to show the surgery inside the head. So they used a window in the wall instead of a mirror! Linda Hamilton and her twin sister are mimicking each other's movements to make it seem it's a mirror image.
(The other use of Linda's twin sister, the scene where the T-1000 fakes being Sarah, is better known)