special effect for film

[Jim Stamos]

we are doing a short film along lines of paranormal activity type. i know theres elaborate expensive ways to do this, but is there any alternatives not costing thousands of dollars to pull off.
want to show someone being pulled on floor down the hall from legs back as if someone has their legs and is pulling them back, theyre screaming with no control of what is being done. of course it has to look like noone is pulling them. im sure expensive ways involve cable etc.
also want to be able to show someone flying back into the wall as if they were thrown.
any sites show this? couldnt find anything on youtube

[Sareesh Sudhakaran]

Haven't done anything like it but here's a suggestion:

1. Get a nude suit/cloth or see through tape/plastic and wrap around leg - something like this:

Nude Body Suit Medium Accessory: Amazon.com: Clothing

 

Nude Body Suit Medium Accessory: Amazon.com: Clothing

2. Use a strong rope, preferably green in color. You can also use lighting and shadows to your advantage by using a thin but strong rope that becomes invisible under light.
3. If you want to change direction along the pull, you'll need a a pulley system on a stand
4. If you can, place a small board with wheels underneath the actor - the rope can be attached here.
5. Get a good 'physical' actor who can sell the shot
6. Shoot a 'plate' without the action
7. Shoot the actual take
8. Chroma key or roto out unnecessary bits and composite with the original.

9. On the other hand, if you can travel with the actor, i.e. camera follows closely, you can also push the actor instead of pulling them.

Maybe that's a start. The important thing is to allow yourself time to experiment and get it right.

[Martin Catt]

As for what cable to use to allow chromakeying it out, let me suggest line trimmer (i.e. Weed Whacker) line. It comes in florescent green or florescent orange, is strong as all get-out, and you can buy it in a bulk pack to get a useful length. It's also thick enough so it won't cut into the talent's skin.

I came up with this idea while pondering a nature mockumentary about the secret lives of the wild herds of shopping carts migrating across the windblown parking lot. In this case, you want the string or cord to be REALLY visible to make it easier to key out.

Martin