Sensors
This is the behind the scenes of Avengers: Infinity War. This is how the sensors were put on the face so that they can generate Thanos's suit.

Before sensors
This was the procedure that Josh Brolin had to go through before the sensors. It is less pleasant than sensors and technology really did save time and efforts, and made it easy for the actor to act.

The sets of Star Wars
Technology really did make the whole movie come out beautifully well. But the artists went through the training before they acted in front of the camera with the suits.

Wounds
This is the sets of Tomb Raider. In this movie, the wounds and the scratches that look so real was manually applied to the skin, where it was needed.

The entrance
Any hero or the villain in the movie is portrayed starting with a dramatic entrance and this what "The Predator entrance looks like from behind the camera.

VFX
The sci-fi movies mostly depend on the green screen because half of the things that we see in the movie are computer generated and this how they direct the scenes where they want to show magic.

Green screen
As mentioned above, green screens play the most of the part in the sci-fi movies and this is how they look like behind the camera, while in the movie we only see the magic that they create via computer technology.,

The props
These are the fake monsters that we see in the movies, are these dummies. They did a good job creating these dummies and much better job at making them look alive.

The artists
This is the behind the scenes of a movie where the artist is making adding details to the mold her created into a creature. It might have taken so much of time and energy.

Makeup
The makeup plays a very important role in the sci-fi scenes as it defines the face as per character's preference and then they enhance it further with editing.