Making believable mirror reflections in floor .......

[pellepiano]

Scenario: I have a image of a model lying on a floor. I have separated her from the background and would now like to make her have a reflection, like lying on a reflective surface ( mirrored if you like ).

Just flipping her on another layer wont work as a reflection, as then the positions of the various body parts wont be correct ( this only work when a photo is taken from the ground level ).

I dont really think its possible to get a true reflection but it does not hurt to ask ( maybe this is why studios place the models on glass in the first place ).

[Metryq]

If you want to cut-and-paste a rough reflection, you can hide its limitations by blurring or distorting the reflection with a filter like "glass." Outside of that, you're right -- if the subject was not photographed next to the plane of reflection there's no simple solution. I love watching special FX reflections in movies, like the T-1000 in the helicopter in T2, or Magneto breaking out of his cell in X2. Those reflections must have been photographed from the necessary angle, then comped in.

[lokki]

Metryq,

Those reflections are CG,so it's likely the designer built an environment that consisted of a flat image of the right parts of the room. Imagine building a huge sphere, and painting the inside with your scene. At the center of the sphere is something reflective - it would look like a 'real' world behind you.

[Metryq]

Lokki, what you are describing sounds more like a panoramic virtual environment, which is very common in movie FX today, from Harry Potter's Quidditch field background to various sets in the recent STAR WARS films. I'd have to look up the helicopter shot from TERMINATOR 2, but I'm fairly certain the reflection was photographed off a mirrored ball -- another common tool on movie sets these days.

The X2 shot of Magneto stepping onto his mirror-like iron "pancake" showed his reflection as well as the room from various angles, so that shot may well have used a CGI figure to match the actor's movements. That would strike me as the easiest method, but then I, ROBOT used some pretty wild rigs to get the flying camera shots for the climactic battle scene.

For what it's worth, Pellepiano, your model probably couldn't have been photographed on a glossy or reflective surface without catching some of the studio lights in the shot. Carl Sagan's reflection is noticeably absent from the glossy floor tiles in the Alexandrian Library sequence of COSMOS for that reason. The FX artists for BACK TO THE FUTURE managed a reflective-floor shot as the Outatime's flaming trails ran between Doc's and Marty's feet.

[lokki]

I thought one of the big deals about T2 was the CG effects for the liquid metal, rather than relying on photographic tricks. Or maybe it was just the motion... don't remember now.

Anyway, it looks great. And I do have to keep reminding myself that there is still a ton of physical ingenuity put into movie effects :)

[Metryq]

And I do have to keep reminding myself that there is still a ton of physical ingenuity put into movie effects :)

Indeed. I'm often thrown off by the techniques used, when I was certain I knew how a particular effect was done. T2 was very cutting edge at the time. The animators already had experience with the "water tentacle" from THE ABYSS, yet the morphs in TERMINATOR 2 were 2D, probably because the beginning and ending "targets" (live actors) were 2D.