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Back to the Future trilogy
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Bud Brewster
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PostPosted: Wed May 03, 2017 5:39 pm    Post subject: Reply with quote

________________________________

I've had some second thoughts about my comment concerning the lifting mechanism the flying cars use in Back to the Future.


Bud wrote:
. . . the producers had to cheat by showing the car lift off before the wheels rotated into position, and gently land as the wheels rotated back into position several seconds before it touches down! It's a little like watching a helicopter's blades slow down and completely stop turning . . . while the helicopter is still three feet off the ground!

But today I remembered my own comment about the floating road markers and skyway signs!





Obviously these objects are not held aloft by any sort of fans blowing downward! Apparently they're all supported by an antigravity system.

And then I realized that the hoverboards were also antigravity devices! ("Like . . . duh, Bud!" Shocked)






And many of the flying cars we see don't even have tilting wheels — like Griff's car for example, which floats down gently onto the street outside the Cafe' 80s.

Apparently there were several different "lifting systems" being used in 2015, probably because some of the cars were older than others. The primary lifting system for all of them was antigravity, with the most advanced systems being capable of lowering the vehicles to ground level with no assistance from a secondary propulsion device.

Griff's hot rod would be one of the advanced ones.

The DeLorean might have been an older system, since it was a "conversion", performed on a thirty-year-old car. Therefore, the tilting wheels were needed to somehow lower the vehicle down the last few feet to the road.

And finally, there was the oldest system, which we see on the jeep that lands in front of Marty during the hoverboard scene. It had to make it's final touchdown with the help of a basic action/reaction rocket engine!








The fact that Back to Future II presented such subtle variations in the technology we see in 2015 is one more example of how complex and intelligent this great science fiction film truly was! Very Happy
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Is there no man on Earth who has the wisdom and innocence of a child?
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Last edited by Bud Brewster on Sun Mar 04, 2018 11:00 am; edited 2 times in total
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Gord Green
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PostPosted: Fri May 26, 2017 12:37 am    Post subject: Reply with quote

From Yahoo News ----

New video shows functional hoverboard soaring above Lake Havasu



Ever since Marty McFly rocked a hoverboard in Back to the Future II, people have been obsessed with attempting to create a functioning hoverboard — with companies like Lexus going to great lengths to do just that. Last year, French inventor Franky Zapata unveiled his Flyboard Air, a fully functional hoverboard that could allegedly travel up to 93 miles per hour and reach 10,000 feet in the air. And last week, Zapata decided to take the board out for a test ride over Lake Havasu in Arizona. The results were wild.
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Skullislander
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PostPosted: Sat May 27, 2017 3:42 am    Post subject: Reply with quote

A reliable, working hoverboard that just glided a couple of feet off the ground would do me personally--remember the ones on sale fairly recently that had exploding batteries?!

Uh-oh----that early version was a no-no.
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Bud Brewster
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PostPosted: Sat May 27, 2017 11:39 am    Post subject: Reply with quote

________________________________

I once had a heated debate with my 25-year-old son when he insisted that the hoverboards were NOT propelled forward by the riders' feet pushing on the ground, the way normal skateboard riders do.

He noticed that the actors (who were suspended on wires, with the boards attached to their feet) frequently didn't really touch the ground, they just waved their feet right above it.

I tried to convince my son that since the riders didn't really need to touch the ground (because the rigging above them is what caused their forward motion), the movement of their feet was just for appearances.

And if you watch closely you can see that the riders are suspended just a bit too high for their feet to reach the ground anyway!

Why? Because if they HAD pushed on the ground, it would have had an unfortunate consequence.

Since they were all hanging down on wires from a moving rig above them, pushing backward with their feet would have thrust them forward on the wires that held them up . . . and then they would have swung back again!

This unwanted swinging back and forth from the rigging above would spoil the illusion that they were gliding along on the hoverboards at a constant speed.

Despite all these reasons to ignore the waving feet that didn't actually push along the ground like normal skateboard riders, my son was convinced that the hoverboards were propelled simply by the rider waving his feet above the ground!

I couldn't convince him he was wrong . . . even when I pointed out that if what he said was true, the whole idea that "hoverboards don't work on water" would be false! Shocked






If my son's misguided idea was correct, traction would be completely irrelevant. A hoverboard rider could just wave his foot in the air and cruise right over any kind of surface — sand, snow, ice, oil slicks, and . . . (you guessed it, folks) water!

Therefore, Marty's frantic foot waving over the pond would have propelled his board forward just as well as it did on the land! Very Happy

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Is there no man on Earth who has the wisdom and innocence of a child?
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Skullislander
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PostPosted: Sat May 27, 2017 11:48 am    Post subject: Reply with quote

There was a nice ground-level FX shot in this second FUTURE movie where a board is dropped and it hovers just above the ground, and close-up of real feet in the background jump upward out of frame, which are substituted in the same take by the foreground motion-control hoverboard and baseball boot-bedecked 'feet' which are filmed 'added on top on the background plate via bluescreen or whatever like the spaceships in STAR WARS!

A very unusual FX shot which I much appreciated.
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Bud Brewster
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PostPosted: Sat May 27, 2017 12:36 pm    Post subject: Reply with quote

________________________________

Yes, indeed, the whole hoverboard scene was beautiful done, and without the CGI effects that are available today.

And while I was writing my post above, which just started out as a comment on my son's error concerning the hoeverboards, I kept thinking of more and more details about the scene which related to the discussion.

For example, during my debate with my son I never thought about the very real need to suspend the actors high enough to prevent them from pushing on the ground so that they wouldn't swing forward on the wires they hung from!

I might have won the argument if I'd thought of that interesting consideration. Very Happy

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Skullislander
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PostPosted: Sat May 27, 2017 1:48 pm    Post subject: Reply with quote

I have never looked into how the hoverboard effects were done---there is a CINEFEX special on the second and third film but I have yet to see it, but yes at a guess it looked like most of the hover-shots were done using overhead 'invisible' wires.

To have done it using greenscreen or similar would probably have looked too artificial I reckon.

The second film is my favorite in the series---it is jam-packed with imaginitive ideas, and topped with a slightly disturbing ambience.
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Bud Brewster
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PostPosted: Sat May 27, 2017 2:41 pm    Post subject: Reply with quote

Skullislander wrote:
I have never looked into how the hoverboard effects were done---there is a CINEFEX special on the second and third film but I have yet to see it, but yes at a guess it looked like most of the hover-shots were done using overhead 'invisible' wires.

Actually many of the full-body shots of hoverboard riders were green-screened, but the close-ups of the boards "hovering" above ground with the riders' feet in view where done with actors on wires, as I described.

And based on this behind-the-scenes photo, they even used real skateboards to create scenes of the riders from the ankles up!
Very Happy



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Is there no man on Earth who has the wisdom and innocence of a child?
~ The Space Children (1958)


Last edited by Bud Brewster on Mon Dec 18, 2017 12:34 pm; edited 1 time in total
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Skullislander
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PostPosted: Sat May 27, 2017 2:54 pm    Post subject: Reply with quote

Ah, very interesting that last still — they must have gone back later and removed the skateboard wheels using motion control separate passes [or something] of identical camera movements, to create wipes to remove the unwanted wheels.

Very ingenious and in many ways more impressive and tangible than today's' almost-all CGI shots.
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Gord Green
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PostPosted: Sat May 27, 2017 6:31 pm    Post subject: Reply with quote

I think they just inter-cut the "up shots" of the actors upper bodies with the wire shots.
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Skullislander
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PostPosted: Sun May 28, 2017 12:58 am    Post subject: Reply with quote

Aw . . . I thought my idea of removing the skateboard wheels was better — were ILM really on a budget with this?!
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Bud Brewster
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PostPosted: Sun May 28, 2017 2:11 pm    Post subject: Reply with quote

Gord Green wrote:
I think they just inter-cut the "up shots" of the actors upper bodies with the wire shots.

That was my thinking too, especially in view of the fact that I don't think the technology for "removing the wheels" existed in 1989. And I don't think any of the scenes in the movie match the shot that would have been made by the camera from the angle we see here, with the street below the "hoverboards" visible.

Besides, the actors are clearly standing on common skateboards, not wheeled versions of the colorful hoverboard props, which were always shown further from the ground than normal skateboards. Very Happy




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Is there no man on Earth who has the wisdom and innocence of a child?
~ The Space Children (1958)


Last edited by Bud Brewster on Mon Dec 18, 2017 12:36 pm; edited 1 time in total
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Skullislander
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PostPosted: Mon May 29, 2017 12:15 am    Post subject: Reply with quote

Hiya Bud:

They 'removed the wheels' from a craft Skywalker and Chewbacca are sitting in as they pass throuh a small desert outback n the first 1977 Star Wars film but the results were not that great then, sort of blurred where the gap where they are 'hovering' and very 'smeary-looking.

Yes the digital era handles this sort a thing a lot better.
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Bud Brewster
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PostPosted: Mon May 29, 2017 9:39 am    Post subject: Reply with quote

________________________________

I believe the scene you're thinking of was Luke's landspeeder when he and C-3PO were pursuing R2D2, and later when Luke, Ben, and the droids drove through Mos Eisley. I remember that scene well from the original version when I saw it in 1977 (and later on VHS). It was a pretty unconvincing FX.

It was one of the many scenes that were restored and enhanced in 2011.






The FX in the Back to the Future II hoverboard scenes were all much better than that, of course. And as I pointed out, the hoverboards were always higher off the ground than ordinary skateboards are, so no matter how well the removal of any skateboard wheels might be done, the results wouldn't resemble what we see in the movie.
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Is there no man on Earth who has the wisdom and innocence of a child?
~ The Space Children (1958)


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scotpens
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PostPosted: Mon May 29, 2017 1:10 pm    Post subject: Reply with quote

Bud Brewster wrote:
Gord Green wrote:
I think they just inter-cut the "up shots" of the actors upper bodies with the wire shots.

That was my thinking too, especially in view of the fact that I don't think the technology for "removing the wheels" existed in 1989.

It probably could have been done with multiple camera passes and a roto-matte, but it would have been expensive and time-consuming.
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