THE SMA FORUM ARCHIVE
Posted by Strider, on 2001-10-28 08:30:47
Footprints in the snow... NMBC style
How was that great shot done where Jack walked across thew snow and left footprints, as he was walking toward Sally on the curly hill? I have been thinking about this, and it would be very difficult, unless there was some sort of trick (isn't there always?)
But it creates an excellent solution to the problem of hiding tie-down holes. :7
Posted by Julian Warren, on 2001-10-31 16:23:39
I have no idea how it was actually done, but if you wanted that effect I guess one option would be to use polystyrene for the snow. Then you could burn out the foot holes using a heated tool in the same shape as the foot (in the same way you can use a hot wire to cut the stuff).
Posted by Nick H, on 2001-10-31 22:40:31
I'd try this: Make a snowfield in a hard material like plaster, textures and coated, with the footprints already there where the tiedown holes are. Fill the footprints with matching loose powder (salt, sugar, baking soda, whatever) and remove it when the puppet's foot goes in. You've only got the actual footprint area to avoid touching by accident, which shoulden't be too hard. Don't know if that's how NMBC did it, but it would work.
Posted by Strider, on 2001-10-31 23:25:06
Yeah, sort of what I was thinking. Maybe plasticene would be better than powder, though. Easier to remove in one chunk. But either way, if you burn styrene or empty pre-existing holes, it would have to be done while his foot is right there. Or would the animator swing it up from the knee-joint, emoty the hole or whatever, and then try to match up the foot again? I guess with a framegrabber this would work. Doesn't it always seem like something that looks so simple onscreen, or even seems simple before you try it, gets really tricky in animation?
Posted by Nick H, on 2001-11-02 03:10:04
Yeah, without frame grabbing it could be tricky. I've got used to being able to put a puppet back in nearly the same position as before, so yes, I'd just lift the foot and empty the hole then place the foot over it, then tighten it down fully the next frame. If it was plasticine, and you had threaded tiedowns and metal foot blocks, maybe it would squish out as you tightened down the foot, leaving a footprint?
Posted by Strider, on 2001-11-02 03:41:14
Or you could set up the shot in a large freezer, using real snow, and rig little tiny heating-plates in his feet...:7
Posted by trikfx, on 2001-12-30 02:35:29
I wasn't on that job, so I can't speak for Nightmare, but often the solution is easier then you think. Most likely baking soda. That's all. The set is sculpted in hard form or the like, with the footfalls pre-placed and hollowed out. Small holes are pre-drilled at the base of the foot falls through the bottom of the set for tie-downs into the the puppets feet. A set of pointers that mark the location of the foot falls is rigged to swing out of the way for the shot. Finally the surface of the set is covered (and tacked down with some spray-mount to keep it in place) with a thin layer of baking soda (with some fine crystal added to make it more "magical". Watch out for sugar, ants really like it) and the pre made foot falls back-filled with it as well. The back fill is left as is, without any glue. Between shots you swing in your pointers to show the way, and as the foot touches the "snow", you carfully bring a tie down up through the pre-drilled hole in the base of the set. Screw it into the base of the foot, snug up the tie down to the underside of the set, and enjoy the magical effect for the next few frames as the puppets foot displaces the "snow" just like you and me.
Piece of cake.
Posted by JohnL, on 2001-12-30 04:48:27
what was the snow in nightmare made from, that would be a good place to start.
Posted by Anthony Scott, on 2001-12-30 20:02:41
I animated shots with snow in the Poor Jack sequence. The snow was made of styrofoam that was sculpted and attached to the wooden set. To create footprints, I just punched thru the styrofoam and drilled a hole to tie down Jack's foot. It was a simple process although I had to be careful not to crush the snow as I climbed onto the set. I made a special wooden platform that I placed over the snow for certain shots just so I could reach the puppet without crushing the foam.
I am not sure exactly what kind of foam was used or the tools that were used to sculpt the foam. Anyone out there know?
Posted by Strider, on 2001-12-31 03:19:48
It's so cool to hear from the guy who actually did the shot! I'm curious... how exactly did you punch through the styrofoam, and did you move Jack's leg out of the way and then line it up again using a framegrabber?:7
Posted by trikfx, on 2002-01-03 22:11:02
Let me expand my previous post a little...
There are a wide variety of foams that vary in density, price and toxicity. Styrofoam, your basic lightweight, low density wunder-material is relatively cheap and available at various art supply joints. Another source is your Home-Depot type place. Ridgid insulation is just styrofoam in tounge and grove sheets. It's probably cheaper in comparison as well. You may have to layer it up to get the topography you want. I've tried different adhesives with varying success, depending on temperature and humidity. Start with hot glue, that should do. You sculpt the stuff with a "hot knife", which is basically a wire taught in a frame like a coping saw. The wire completes a circut and acts like a resistor, so it heats up. It works great on low density foam. You can buy both a hand-held and bench top version from a company Micro Mark (as well as a whole bunch of other goodies). For fine details, keep some old butterknives or other little metal shapes hot on an electric hotplate; yes, it gets a bit messy, but it's quick and fun. Work in a ventlated room; your Mom would be pissed if she knew what you were breathing. If money were no object, you would buy nice 2'x3'x10" dense foam like Ren Foam at $200 to $400 bucks a pop, and mill it with a CNC router. The really good stuff is almost as dense as wood, and machines the same way. Whatever you use, even if it's wood scraps, fill the voids with lightweight spackle, prime the surface with flat white latex paint, and finish it up with baking powder. For that, use an aerosol adhesive like 3M spray mount, which you can get at Staples (for usually cheaper then an Art Suppy place). Some aerosols will eat some types of foam but you were smart and laid down a coating of latex paint first so you should be OK. Spray an area, sprinkle a generous amount of baking powder over it, and move on. When your done, wait 15 minutes and then vacuum up the excess with a shop-vac, keeping the hose an inch or so off the surface. Stand back and behold your winter wonderland. You can add glitter or fine crystal (silica) in with the baking powder to make it glitter.
The Nightmare Before Christmas approach used by Mr. Scott seems fine; most animators I've worked with were a little reluctant to lock in there puppets performance a bit by pre-drilling where the foot falls will be. In this case though, By setting up cavities for the footprints in advance and backfilling them with your powder composistion, you get a really cool advantage of allowing the snow to move in a very realistic way as you compress the foot into the snow with the puppets own foot, instead of punching out a footprint. You would just push the foot through the snow like your own foot, connecting with the tie-down out of sight of the camera (and yourself!). Plus, if you're good with spray-mount, you can layer over the footfalls with a couple light passes, so that when the foot contacts the snow, it breaks though a little crust on the surface.
At the very least, you can use these tips to make nice Nativity Scenes for next Christmas...;-)
Posted by Anthony Scott, on 2001-12-31 14:01:29
I can't remember exactly what I used to punch through...probably a wooden tool of some kind. I did use a framegrabber but I also gaged the puppet so that I could keep track of all the pieces of torn cloth as well as it's legs. Here is a photo from the sequence.
Posted by 1, on 2001-12-31 23:30:01
When I visited Peach Productions and saw one of the elf set houses, Webster said they used hot knives to cut the foam. The reason I remember is because I mentioned they must have sanded the foam to get the smooth round curves. And Websters reply was that they used the hot foam tools only and that he was amazed too. Not sure if that was the case with every snow piece made, but at least some of it was done that way.
Posted by Squee, on 2002-03-18 19:03:00
wow, anthony, youve just become my personal hero. That scene in Nightmare always amazed me, because each little scrap of cloth on jack's santa suit flowed so well!! It was awesome :D
"I could've told you, Vincent, this world was never meant for one as beautiful as you"
Posted by JohnL, on 2002-01-01 08:43:05
anthony do you know whether the styrafoam was covered with anything to give it an icey look? especially the snow one the houses in christmas town. it looks like theres glitter in it.
Posted by Anthony Scott, on 2002-01-01 14:52:36
There may have been glitter in Christmastown snow. The "What's This" sequence was shot a year earlier than "Poor Jack" so they may have used different methods then. Also, Christmastown was a different world than Halloweentown or The Real World. They were all designed to have their own distinctive look.
Posted by snoutmaiden, on 2002-03-20 06:21:21
are you AJ by any chance? cus of the squee reference. hmm. perhaps i should go look at your profile and find out.
well i did that, and you don't seem to be AJ. sorry to disturb you.
i'm gonna go sit over here now
Posted by Squee, on 2002-03-20 20:41:24
nope, am indeed not aj. you can call me... um... Mo. Thats not my name though. it would be a fun name to have... sorry im not anyone you know! *trundles to the other corner*
"I could've told you, Vincent, this world was never meant for one as beautiful as you"
Posted by snoutmaiden, on 2002-03-21 05:58:43
hows your corner? mines not so good, turns out it's got a toilet in it. if only i'd looked where i was going. hope you're having better luck.
Posted by e_rex, on 2002-01-04 08:47:16
You know, there's also polyurethane foam in cans sold to fill spaces. It might make nice snow drifts, etc.
Posted by trikfx, on 2002-01-05 00:50:43
The only problem is that the stuff from the can, "mountains in minutes" I think one brand is called, and another a standard type of gap insulation foam for windows and such, is that a) it's messy, and hard to control, and b) it doesn't sculpt well (at all, really) after it cures, tending to be, I don't know how better to describe it... un-fun. Perhaps you'll get better results. I've found it more useful for what it was intended for; filling gaps. It sticks to pretty much everything, so it comes in pretty handy; as long as you don't have to re-work it later on.
Posted by Strider, on 2002-01-07 02:01:46
Here's something I've though of, but haven't tried yet:
Sculpt a set from paper mache, over a form of crumpled and taped newspaper, then when it's dry flip it over, remove the crumpled paper, and fill with Great Stuff (that's what it's called 'round here). I would then press a big piece of flat cardboard (or plywood) into it to form a flat bottom. Anything that squeezes out the sides can be cut off after it sets up.
There's this stuff available at Monstermakers.com called foam urethane resin. Apparently it is a two-part resin system that foams up and expands to like 30 times its original volume. Has anyone used this? I was considering using it for large scale sculpture, as long as it forms a 'skin' against the inside of the mold.
Posted by e_rex, on 2002-01-07 08:44:12
This foam is a filler. What you want is an agent to form a skin, then the foam as backing. Check out suppliers; BJB for example to get the materials and advice on using it. I don't have an address, but any search engine should turn it up for you.
Posted by Nick H, on 2002-01-12 03:15:53
I worked for a propmaker ages ago in England who made architectural ornaments (for stage sets) by getting them vaccuum formed in styrene sheet, then filling the vacform with expanding urethane foam to give it rigidity. You could also do a very light fibreglass coat in the mold, then foam fill it. For free form granite-like rockwork, I've also built up the foam over a chicken wire shape, then fibreglassed the outside and finished off with a sandy gelcoat, to give it a tough skin that could stand up to kids clambering over it. In the background of a set, you could leave it unskinned, it's easy to poke trees into it that way. Florists use blocks of it, coloured green, to poke plants into. Beware, 2 part foam gives off toxic cyanide gas while it expands.