jerk vests, flying refrigerators, etc.Re: [Beowulf] Re: "hobbyists"

[Peter St. John]

Jim,
Well I was thinking of low-budget, Hong Kong in the 70's type special
effects, and just meant that things don't really fly around as much as we
see in the movies. That said, I'm a huge fan of stuff flying around, so
thanks :-)
Peter

On 6/24/08, Jim Lux <James.P.Lux at jpl.nasa.gov> wrote:
>
> At 09:25 AM 6/24/2008, Jim Lux wrote:
>
>> At 02:31 PM 6/20/2008, Peter St. John wrote:
>>
>>> The destructive radius of Little Boy was about total, up to about one
>>> mile radius, and tapered down to light at about two miles. So being in a
>>> lead-lined steel container at 2000 meters might be OK for Indiana.
>>>
>>> In all action movies, blasts throw people unhurt for long distances; when
>>> that much force (to impart that much momentum) would kill you. That part is
>>> just conventional Hollywood. I could teach RGB to kick me so that I fly
>>> through the air as in a Bruce Lee movie; it's a stunt, and real kicks
>>> reallly hitting drop you like a sack of potatoes, I've seen it. But not in
>>> movies. Similarly bullets, they drill holes in you, if they pushed you
>>> through the air the recoil would do the same to the shooter.
>>>
>>> As for the scene's good taste I can't say, I haven't seen the movie yet
>>> :-)
>>>
>>> Peter
>>>
>>
>> As someone who used to work in the business of doing this sort of thing
>> (e.g. physical effects) for movies, TV shows, and commercials, you can
>> assume that whatever you see on screen is specifically designed to "look
>> like" what the director thinks will create the correct impression in the
>> viewer. (e.g. real rain is invisible on film, for all intents and
>> purposes..)
>>
>> For blasts (or kicks, etc.) flinging folks about, they use what is known
>> as a "jerk vest" (for the high third derivative of position, not to describe
>> the wearer) and bungee cords, springs, hydraulic winches, etc.  Note well
>> that the effects tech just runs the gear.  A stunt person (aka human
>> sandbag) survives the loads (and gives thanks to Stapp).
>>
>> To fling things about, we used a variety of things.. air power is popular,
>> so is gunpowder. (look under a car that flips over for the piece of
>> telephone pole used as the piston in a one-shot internal combustion engine.)
>>  Speaking of refrigerators, air pressure is just fine for a hundred meter or
>> so launch.
>>
>
> For some examples:
> jerk vest test
> http://www.reelefx.com/index.php?c=effect.view&id=260
>
> refrigerator launch
> http://www.reelefx.com/index.php?c=effect.view&id=124
>
> http://www.reelefx.com/ gives a lot of examples
>
>
> http://www.reelefx.com/index.php?c=effect.list&id=15
>
> has variety of specific effect tests.  Search for 'air mortar' for launches
>
>
> Naturally, I'm particularly proud of the tornado and multicam, since I
> helped make them...
>
> http://www.reelefx.com/index.php?c=effect.list&id=13 tornados
> http://www.reelefx.com/index.php?c=effect.view&id=153 from Swordfish
> http://www.reelefx.com/index.php?c=effect.view&id=169 (stuff done more
> recently, now with digital cameras, which makes life MUCH easier..)
>  Eadweard Muybridge would be proud of us.
>
>
>
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