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Old May 4th, 2006, 06:42 PM   #1
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Special Effects-Sparks

I am looking to produce an electrical short, here is the scenario…
The talent brushes a group of wires and several wires “short out.”

Has anyone done this or know how to create the effect?

Thank you,
Bill
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Old May 4th, 2006, 10:15 PM   #2
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Um, turn off all the lights? Just kidding. A few quick flashes of bluish light and maybe a warm glow from the hot metal of the wire for a second or two is what a short looks like. I'm not stupid enough to have ever caused a short, but I've heard these things from friends and people like that. Yeah, that's it.

If you know anyone with a MIG welder, that will give a nearly perfect effect if the welding gas is turned off. With the gas off, the steel immediately oxidizes and pops and sizzles after the blue flash of the electric arc. Needless to say, if you do this with real special effects, electric arcs add an element of danger. You could instead use something like a small camera flash with some CTB gel added then rotoscope a bit of a glowing spark at the point of contact. Have the flash eminate from as close to the wires as possible and it should work. Fortunately, these things are easy to test.
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Old May 5th, 2006, 09:31 AM   #3
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Marcus,

A MIG welder is one of the ideas I came up with as I have one.
I would however like the effect to be in place and be repeatable.

One thought I had was to use a condenser, charge it up use the effect then there would not be any lingering voltage to deal with..
I should add that I am not looking for a dead short but an intermittent one.
A second idea was to use an electric match without the pyrotechnics just the shunt between the wires. I was thinking that might give me a pop and some sparks.
Anyone out there making their own electric matches?

The scene is this, there had been an auto accident (there is smoke and fire under the hood (I have this looking good)) the talent goes back to the vehicle to retrieve his golf clubs and is scared back out of the vehicle when sparks fly from under the dashboard.

Thank you for replying. :-)
Bill
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Old May 5th, 2006, 09:47 AM   #4
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Sparks from a car's electrical system aren't dangerous unless they start a fire. Anyone who knows how to jump-start a car probably has this information. I know most movies pitch to morons, but you may also have some smart people watching. Also, anyone that goes into a burning car for golf clubs will look insane and probably wouldn't be scared by sparks. Perhaps the trunk could have some fire also? Besides, what would cause sparks in the trunk?

I hope you are faking the fire under the hood or perhaps this car has had all the flammable stuff like fuel and rubber removed?

Has anyone here witnessed a real car fire? The fire has intensity unlike anything else you have probably experienced. I drove past a burning car a few lanes over and the heat coming from it (through tinted windows) at that distance (~40 feet) was more intense than the heat from the sun on a cloudless day in summer. No sane person could get within 20 feet of a burning car without fire protective gear and some water. When cars go up in smoke, they really go hard and fast.
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Old May 5th, 2006, 10:37 AM   #5
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Well let’s see… I pulled a drunk out of a burning car once and for my efforts he took a swing at me because I left his glasses in the consol. So yep I have seen a burning car.
I also was a SCCA Marshall and am quite familiar with gasoline and flame.

The engine fire is done with lights and smoke (fog.)
It is meant to be more of a smoldering fire than a fully involved vehicle fire and goes out fairly quickly.
I did the test with my car so you can be sure I was very careful, for the shoot I want the engine and fuel tank removed just for safety and ecological reasons. (No oil/fuel no cleanup.)
The driving shots will be done on a trailer. We will be using a wreck I just will not show the front end till after the crash. :-)

I don’t write it, I just give them what they want. :-)
His clubs are in the back seat. He sees the sparks as he is leaning in.
In the FWIW column it is a comedy and was funny when I read it.

Thanks,
Bill
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Old May 5th, 2006, 04:04 PM   #6
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I recommend checking out http://www.detonationfilms.com/ They have free video clips you can composite in. This is much safer.

That's also not as fun. For some DIY pyros, use thin strips of aluminum and a 12 volt battery. Use that to ignite flint that you gently scrape off. Flint dust makes nice sparks. You could also try fine magnet wire with a shellac coating. Knock some of the coating off a bundle then short out the 12V.

-Adam Keen
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Old May 5th, 2006, 07:30 PM   #7
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Adam,

Thanks, I had for gotten about that site.
Thank you for the suggestions as well.

Bill
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Old May 5th, 2006, 07:48 PM   #8
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Instead of using electrical sparks, try this instead. Using a black back ground, take a grinder to some steel, and shoot that. You can then lay it over your footage, shrink, position, and key out the black.

A little safer than mucking with electricity, especially if you're like me and Tim Taylor.
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Old May 6th, 2006, 03:08 AM   #9
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Thanks for the safety reassurance, Bill. Also, regarding realism - "In the FWIW column it is a comedy and was funny when I read it." Enough said. All is fair in a comedy. I've been seeing ridiculous things in "24" and the logic flaws really make it low-brow but I don't think they intend it to come across that way.

I really like the use of a pre-wrecked car. If the audience only knew...

I like Keith's idea, but use sparks from the MIG welder against a black background instead since they are genuine electric sparks. On the set, you could use a flash or strobe to tie the keyed-in effect into the scene. Don't forget to record some sound in case it sounds like a nice spark.
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Old May 6th, 2006, 07:58 AM   #10
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I am getting some good ideas.
I will shoot a test with the grinder; I passed on that idea thinking it would not be realistic. However having Keith bring it up again had got me thinking about it again with a fresh perspective.
I will fire up the welder as well and see what we get; it looks like on detonationfilms.com they may have used a welder or plasma cutter for some of their effects. Thinking about it if I take a piece of steel and paint it black and drill a hole through the center of it, I could strike an arc on the wall of the hole from the back side.
Then the sparks would shoot out like I want.

Just one more note about safety, I am a mother hen about my talent and crew no one on a stage or set has ever been hurt when I have been in control of it and they never will.
As for electrical stuff my father owned an electrical business, I could ruff wire a building when I was eight years old, I could finish wire it by Jr. High. We do this for fun and it is no fun when people get hurt. Enough said. :-)

Thanks,
Bill

Thought I would add...
Day time test my car shot in the front yard.
http://cinebydesign.net/film/day-smoke-1.jpg

Night time test with "fire" ((frame grab) please for give the lenes shade on the right)
http://cinebydesign.net/film/night-smoke-1.jpg

Night shot of test set
http://cinebydesign.net/film/set-test.jpg
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Last edited by Bill Hamell; May 6th, 2006 at 08:52 AM.
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Old May 6th, 2006, 10:35 AM   #11
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I looked at your photos and came up with a bunch of ideas.

A trunk/dome light could come on when the trunk is opened. It would illuminate the actor a bit. Suddenly, when the spark occurs, it would flicker out. That could add to the effect of the scene. The actor would still need to be lit by the key light and maybe a hair light/kicker. You could probably tap into the dome light itself or fake one with a studio light in the car. A switch could be sent out to a gaffer.

Regarding the key light. I really like the first shot in the daytime (evening) where the sun is streaming through the steam/smoke. I also think your key light reveals itself too much since the rear corner panel is noticeably brighter than the front of the car. There is also a big highlight on the rear wheel that gives away the light's position. Simulated moonlight seems to work better if it is side or back lit. Perhaps you could move it to camera left instead of camera right. That way there could be some streaming shadows cast from the tree through the smoke. I also think the light needs to be moved further away so the inverse-square effect is lessened. The part of the scene closer to the light is significantly brighter than the rest. It seems that your light is bright enough to deal with greater distance.

I like the look of the "fire" and would like to see some cast in the wheel well and under the car to accent those details and make it a bit more dramatic. The bent hood revealing the light is perfect, but I would like to see a bit more.

Regarding safety, I think the sandbag slipped off the leg of your key light. ;)
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Old May 7th, 2006, 01:52 PM   #12
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I like the dome light idea I had not thought of that.

I agree completely with your assessment of the key light.
I did see that highlight on the rear wheel; however my goal that night was the engine fire. I did not really care about it just made a mental note of it.
Moving the key to camera left and back… we agree again.
I had debated whether to use a 1k or a 2k for he test I went with the 2k so I could pull the 2k back or just use a 1k instead.

Here are my thoughts…
Take what is the key now and make it a back quarter light camera left placed high and hitting just before the backside of the vehicle. Then light the talent with a combination of a side light (fill) camera right and a quarter light (key) camera left, letting the backlight act as a "rim" light as well. The talents lights will have to be flagged to keep any light from striking the vehicle or the ground. They will be the “unknown light source.” :-)

The wheel well light is also a good idea I will work on that. I only had three working lamps for the fire (more parts due here Tuesday UPS.) One for under the vehicle is a must.

Sorry not going to bend up my hood for the test!!! :-)
Good idea though.

Regarding safety, good eyes I had removed that bag to start the tear down when, I remembered I had not takes stills of the set-up. I was the only one on the test set and if there was even one more person on set I would have replaced it.

Bill
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Old May 7th, 2006, 08:20 PM   #13
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I was just giving you a hard time about the sandbag. :)

I didn't mean to imply that you should bend the hood further. It looks fine as it is. People know there is not usually a gap between hood and fender and a fiery glow coming from that gap is a perfect indication that all is not well. The "more" I mentioned is more "fire" light coming from under the car.

I agree with the 2k placed further from the car to reduce the brightness ramp-up that occurs with close light sources. The inverse-square law is often my biggest problem with lighting since I need to put my low-budget weaker lights close to the talent. It is always a struggle to prevent giving away the light source when a big highlight suddenly appears when someone walks too close.
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Old May 8th, 2006, 08:07 AM   #14
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i did this with a preshoot for a couples wedding video (of all things)

the thing to remember is that sound wil play a major part in this..

I used day for night effect chains (as the lights went out, so did the luminance of teh shot)

I also used Particle illusion to create the spark bursts (had a load of FLurou lights short circuit and blow their tubes..

PI is great for this, and blending it with PI, worked a treat. PI illuminated the "darkened" areas and made it look quite authentic

As ffor grinding through a metal plate.. u dotn have to do this.. u can do all these kind of effects in programs like fusion, PI, Combustion etc etc... and yes, they are photorealistic...
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Old May 10th, 2006, 03:57 PM   #15
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Marcus

<I was just giving you a hard time about the sandbag. :)

That is how I took it. Still good eyes.
I was spinning humor on the hood thing.:-)

I agree more fire more flames, bigger, hotter burn that puppy down!! :-)
Seriously it needs to be brighter and needs to go into the wheel well and on the ground. My starter sockets arrived yesterday I will build the flicker box(s) this weekend. This will allow more lights to be used.

I spoke with Mario from Eliminator Lighting he suggested I use a Hazer instead of a Fogger for the longer scene times. It seems that all foggers have to reheat within 30 seconds to a minute and a half depending on the heater size. However hazers do not use a heater and can run for longer times so I will start looking for one. Eliminator does not make one. Their fog machines work well though.

I was lucky to get the Studio 2k a bargain at $175 I was thinking of backlighting the smoke through a 4x4 of Rosco 3011 tough silk orientated vertically I’m hoping to it will create a ray effect.
Then use a 650 and a 300 for the talent.

If the weather is good (it is supposed to rain this weekend) I will shoot a second test the following weekend.

Peter,

I download the Particle illusion demos which did you use Particle Illusion or Particle Illusion SE?
I could easily do the SE version at $99 and probably afford version 3 at $399, Combustion at $950 is out of the question.
Thank you for the suggestion.

Do you have the project .ipf files available and if so would you be willing to let me view your work? I would not use them just learn from them.

One thing I was disappointed in was you can not skew the particles on the Z access.
I would like to place the particles canted from back to front. Maybe I just have not worked long enough to figure out how to do this.

Thank you to both of you for the help.

Bill
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