[reader50]

Originally Posted by andi*pandi 

another odd private message I got on facebook. The most persistent people are cleaners and duct vent spammers.

Sounds like they're full-service. Should you respond, ask if they'll launder money and clean evidence for you. Imply bloodstains on furniture & carpets. Cleaned site must look like there was no violence. Throw in some Mob terminology - gotta protect the Family.

Two can play the creep-out game.

Should they ask for a site pic, maybe subego can fake up a scene for you. So it looks like someone had been tied up in an office chair - some rope & cut nylon ties lying about. Some large-ish blood stains. Maybe an empty acid jug partially visible on the edge of the pic.

[andi*pandi]

Since it's facebook and my real name, maybe not!

[subego]

“I will respond with lots of love and dedication” is just perfect.

[subego]

We need an effect where a bullet shot at the cats hits the ground about a foot in front of them and plows up some dirt.

I pitched using actual explosives, but got vetoed.

I’m convinced it can be done safely, but the dealbreaker is the pressure it puts on the parents.

Oh, well. CG then I guess.

[reader50]

During the filming of Inception, they had the cafe scene in Paris. The film makers wanted to use explosives for when the scene tears itself apart. Surprise, surprise - they could not get permission for explosives within Paris.

So they used compressed-air charges. CGI was used to add extra junk into the air, but the main work was done with compressed air. The scene did not suffer from the change.

Compressed air isn't hard to come by, the hard part would be limiting the output volume to a fraction of a second. To simulate an explosion. Some kind of fast-acting valve perhaps. Or a super-tiny reservoir, limiting the "explosion" by available volume. Say, the volume of a short tube between two valves. The charge-up valve you fill normally, then kill. And the solenoid release valve.

[subego]

My original idea was to stomp on some form of bellows.

Ironically, I feel the risk profile for this is essentially the same as a tiny explosive. Both are equally capable of chucking debris into someone’s eye.

[andi*pandi]

you don't want to do the old movie cutaway (cats eyes widen, gun fires, cut to closup of puff of dirt at their feet) or?

[subego]

I don’t know the exact details, but as imagined the shot is wide enough to see both cats and the area which gets hit.

We considered greenscreen (well, bluescreen, because grass is green), but this is a job for sodium vapor.

[ghporter]

With a big enough bellows, and a big enough “stomp”, you can make the effect work. What reader said about releasing the air “all at once” is important if you’re throwing a bunch of stuff into the air. But just simulating a bullet hit should only need a little air (comparatively speaking).

This one should be more than enough.

Now the caveats: you have to pipe the air to where it’s going to blow the dirt up; I think 1/2 inch polyethylene irrigation tubing is a good choice. You can just put an elbow fitting on the on-camera end of the tubing (with something to keep the dirt from filling the fitting) and bury it - along with the rest of the tubing. Pro tip: a square-bladed shovel can make slits in sod that disappear after you place your tubing in them. We did this to hide/protect XLR cables for outdoor PA setups.

So I would first plan where the effect is going to happen, to get an idea of how much tubing you’ll need. Then experiment with connecting the bellows output to the tubing so you can keep the bellows output from popping out of the tubing connection when you stomp on it.

Once you get that figured out, assemble the tubing and elbow, bury everything well past “out of frame”, and then connect the bellows to the tubing. Ideally this setup would let you rehearse blowing out a clump of dirt and sod several times, tweaking as needed to get the right look.

Alternatively, if someone knows where you can get an inexpensive pneumatic valve - preferably electric - then I’d go with the same kind of tubing, but connect it through the valve to a compressed air tank.