July 13, 2010
making a replacement face kit
by sven at 3:45 am
I've discussed mold design for my film, The Beginning. In this post I'll document how you take resin castings and turn them into a full replacement face kit.
Fig.1: The mouths in my face kit are based on the visemes described in Preston Blair's classic book, Cartoon Animation. Every other set of mouth shapes I've encountered in books and online is derivative of Blair's seminal work. Many authors simplify Blair's shapes in ways that I consider mistakes; for instance, identifying vowels by alphabet letter rather than phonetic sound. For my purposes, I decided I could simplify the set very slightly and get away with 12 mouth shapes.
Problem: How do you name these mouth shapes? —Particularly the vowels? I decided for this project to do some in-depth research on how dictionary pronunciation guides spell out phonemes. The wikipedia entry on Pronunciation respelling for English proved extremely helpful… To my surprise, it turned out that there is no universal system! One system may define "ay" as sounding like pay — whereas another defines it as sounding like pie.
For my purposes, I decided that a simple and elegant approach would be to denote long vowels with capital letters, and short vowels with lower case letters. One additional vowel is required, though: OO/oo. Here's my pronunciation guide:
I also found it useful to reorganize the various phonetic sounds into four categories… Consonants, vowels, consonants that use vowel mouth shapes, and vowel sounds that are actually made by combining two other letters' sounds. Here's my cheat sheet:
Now that you understand how I've chosen to notate and organize phonemes, here's the list of the 12 mouth shapes I finally settled on:
- A e
- a
- BMP
- E i Y
- FV
- H(-o,u)
- L
- neutral
- O o
- OO oo QW
- u R
- X
Fig.2: I had originally planned to do the replacement faces as single-piece masks. The problem with that plan, though, is that eyebrows would have to be re-applied every time the mouth moves. No good! So I decided to try the method used in Coraline: doing the forehead and lower face as two separate pieces.
I took a casting and cut it in half with a craft saw. The forehead gets discarded. I used a belt sander to smooth the rough edges of the lower face and make them perfectly flat.
Fig.3: The half-face part I just made goes into the mold as a placeholder. I use a brush to thoroughly paint the part with vaseline, then do a casting of just the forehead, which will be a second placeholder. The two parts match up exactly now. Had I used the forehead piece that was cut off in fig.1, seams would have been much wider.
Fig.4: Working with silicone, polyester resin, and solvents is nasty, messy, and toxic. In addition to wearing my usual safety gear, I purchased a large metal tray from a restaurant supply store, on which to do all my chem work.
To make cleanup easier, I tried lining the pan with wax paper. Unfortunately, chemicals go right through it. In the future, I may try laying down Saran wrap or something similar instead.
Fig.5: For casting the mouth and forehead pieces, I found that 10ml of part A combined with 10ml of part B gave me about the right volume. You need to have some overflow that will exit though the sprue holes in order to get a good casting. The area around the mold gets progressively messier with each casting.
Fig.6: It takes at least an hour for the resin to fully cure. I found that the pieces were firm enough to demold at 30 minutes. Do not trim off flashing at that point, however — the curved casting is likely to get deformed by your grip while you work on it.
It took 15-20 minutes to release each casting, clean the mold, and pour in another batch of resin. So turn-around time for each part was about 50 minutes. Needing to make 12 mouths, 3 foreheads, and some spare parts to have on hand, this was more than 2 solid days of work.
It was a fairly frustrating part of the fabrication process… Not because I had to wait, per se — but because I had to repeatedly take off the gloves to work on a B project, then interrupt myself to put the gloves back on when the each new casting was ready. No sense of flow was possible. It would be preferable to be working on two casting processes simultaneously, to avoid switching gears so much.
Fig.7: In all, I got 24 good castings out of the mold before wear and tear got too bad. Studying the mold interior, I think I see what went wrong. When I made the mold, I painted a thin detail layer of silicone onto the sculpt, then covered that with a thicker layer. Bubbles were trapped between the thin skin and the thicker one… So most damage was from the thin skin tearing away to reveal the air bubble trapped behind it. Use of silicone thinner probably also helped weaken the material.
Fig.8: We don't need a set of identical faces — we need them resculpted with different mouth shapes and eyebrow positions. For this job, I tried a flexible shaft attachment with my Dremel roto tool for the first time. I was pleased — it was much easier to wield the tool while carving.
Fig.9: Resculpting a face involves carving away excess material…
Fig.10: After excess material's been removed, new bits can be built up by adding epoxy clay. I used Magic Sculp, which has about a 4 hour cure time. Apoxie and Milliput are roughly equivalent leading brands.
Fig.11: Eyebrows didn't require any carving. They just sit on the forehead.
Fig.12: Using such tiny quantities of epoxy while sculpting, getting equal proportions of part A and part B can be tricky. I found it useful to flatten out dabs of epoxy on a piece of gridded paper and then use the guide lines to help me cut them to size. (Good free graph paper PDFs are available from incompetech.com.)
Fig.13: Are the face kit pieces working out? As an initial test, put the pieces back onto the interior mold face. I was pleased at this point to see that registration's pretty accurate.
Now we can proceed to making a base for the faces.
Fig.14: During the mold-making process, I made a Super Sculpey placeholder to establish the thickness of the faces. When it comes time to make a base for the faces, the Sculpey piece becomes useful again.
Fig.15: The base for the faces merely needs to support the eyeballs, so I put some Klean Klay into the mold, atop the Sculpey placeholder, to create some extra space. To set up walls around the edge of the face, I just used some tape. Tiny magnets were placed in their sockets in the Sculpey, and additional magnets were placed atop each of them. The second layer of magnets create sockets in the base.
Fig.16: These magnets are so powerful, if they come too close to each other they leap out of their sockets and go flying across the room. Putting them in place was a bit tricky! Ultimately what worked best was to use a dental tool to maneuver them into place. I'd then pull the dental tool away while holding the magnet down with a toothpick.
Fig.17: Pour part A and part B of the resin into two separate cups, then mix them in a third. Fill the mold.
Just before making the base, I discovered that all my resin hardener had dried up, and I had to go out to buy a new batch. The resin and hardener (part A & B) are sold as a set. I thought I'd use up the old resin before breaking in to the new… But when I mixed what I thought was part A with part B, I discovered — much to my chagrin — that I'd only mixed two cups of resin base together without any hardener. TAP plastics has switched which material they label as A and which they label as B!
Cautionary tale: double-check that you know which material is A and which is B before combining new and old materials!
Fig.18: It's interesting to watch the resin cure. I would have expected it to start congealing at the edges of the mold… But actually it turns white in the center first.
Fig.19: Here's the resin after it's fully cured. It's noticeably whiter than castings I did with the older materials. That clue turned out to be pretty important later on when things started to go seriously wrong…
Fig.20: Here I've separated the base and Klean Klay from the Super Sculpey placeholder.
Fig.21: Here's the face's base after it's been cleaned up. Studying it, I realized that the bulge in the middle is unnecessarily large. With more flat area, there'd be more room for drilling tie-down holes.
Fig.22: I used the Dremel roto tool to carve away more material. If/when I do this again, I'll try to remember that the only thing needing to go in the hollow space behind the mask is a support for the eyes.
Fig.23: Here's the whole kit ready to be painted: 12 mouths, 3 brows, and a base. That useful organizer that they're in was less than $2 at a jewelry supply store. If you look closely, you can see that I've drilled two holes in the base for tie-downs.
Fig.24: Before painting these faces with acrylics, it's a good idea to spray them with a layer of primer. To protect the magnets, I covered them with little sticker dots.
Fig.25: I sprayed the backs of the pieces with black primer and the fronts with white primer (Games Workshop brand). I was thinking about how theatrical masks tend to have their interior painted black. However, almost immediately after priming, I realized that replacement faces are different. You want everything to be flesh-toned — to camouflage the interior, in case the camera accidentally glimpses it through a gap between the eye and the eyelid. Black was a mistake.
Fig.26: The day after priming the parts, I made a horrifying discovery. The primer was wet — completely uncured, it seemed. As I was applying acrylics, black fingerprints kept showing up. What a mess… I had no option but to strip off all the paint and primer and start over.
Fig.27: At first I thought that the problem was the primer. Did I not shake it long enough? Was it too hot on the day I sprayed? Too humid? Should I have washed the parts with soap before spraying? Research told me that primer can be fussy, and any of these mistakes might cause problems.
But then I noticed that the pieces were leaving oily marks on a piece of paper. Now I'm pretty sure that the primer wasn't the main problem. What's going on is that the resin chemistry was off — something is leaching out of the resin that either prevented the primer from adhering, or dissolved it overnight.
Remember that my old batch of resin hardener had dried out? The whole story is that some time ago, I was unable to open its container. So I cut a hole in the jug, and then later resealed it with tape. But the tape didn't adequately prevent evaporation. As the hardener reduced down, I was no longer creating the proper mix by combining equal parts of A and B. Comparing leftovers from an old batch with leftovers from the new batch, it's painfully obvious that the old batch is yellow — a sign of bad chemistry.
Lesson learned: Make sure your materials aren't past their expiration date! And make sure to keep them tightly sealed between uses!
Fig.28: With so much time invested in this project, I couldn't just give up. I had to try to salvage the parts. It took five hours scrubbing with CitriSolv and an old kitchen sponge to strip off all the ruined paint and primer.
Fig.29: Even after the parts had been cleaned, there was a good deal of staining that's impossible to remove. It was pretty demoralizing to see my shiny new parts looking so grubby.
Fig.30: For my second attempt at priming, I was extra careful about shaking the can, heat, humidity, and cleaning. I washed all the parts with dish soap and dried them thoroughly with a hair dryer. The heat of the dryer seems to make more oils sweat out of the resin, so I tried to use it sparingly.
This time I went with Krylon white primer, feeling that it might be a more trustworthy brand… Even though it probably wasn't Games Workshop's fault that the first priming failed.
Fig.31: While re-priming the parts, I noticed that there was pitting on some of the surfaces. I think this must have occurred when I was scrubbing with solvent. In trying to solve one problem, I created another. If I wanted, I could fill all those tiny holes with epoxy… But by this point, I just needed to get the project done, and couldn't afford to be a perfectionist anymore.
As a final step, I used epoxy glue to fix tiny magnets into the backs of the face pieces — taking care to make sure that all the polarities were pointed in the same direction.
Fig.32: The white primer has survived better than the black did… But I'm seeing signs that it's also beginning to "sweat" a bit. Further proof that my main problem is bad resin chemistry.
Fig.33: My original plan was to give the puppet eyes, hair, and a naturalistic paint job. However, I only allotted myself a month for this experiment, so plans changed. The faces are striking when they're all white; I determined to do a lipsync proof using that look.
I figured I should at least finish off the eyes, though. The plan was to paint 3/8" wooden balls with enamel paint. Pupils would be made from black dots of paper, which could float on a thin coat of vaseline.
Fig.34: I drilled holes in the back of the eyes, planning to fill them with magnets. I temporarily hot glued toothpicks in those holes, so I could easily dip the balls into the paint. I dipped each ball three times, which created a gorgeous glassy look. However, it took days for the paint to really cure — and even then, the paint was more vulnerable to marks than I'd expected.
Fig.35: It turns out that with those extra layers of paint, the eyes became too big to fit in their sockets. Next time, I could either start with smaller balls, anticipating the size change — or I could just use delrin/acetal plastic balls and skip this issue altogether.
Fig.36: Onward to photography! For this project, I wanted to create a set of 36 face photographs for animation. That's 3 brows times 12 mouths.
I set up the camera as a downshooter and used Dragon Stop Motion as a video assist. Technically I didn't really need to use a framegrabber — but it made aligning the faces between shots a good deal easier.
The magnets work perfectly for fixing the face parts to the base. However, due to one of the base's magnets being a slightly tilted, the lower face can slide a little to the left or right. I think an important addition to the design would to add hemispheres (or something similar) to the edges of the face pieces, to help them physically key into the base.
The light, incidentally, is set into a handy little fixture that is nothing more than a socket and a plug. Very cheap — less than $2 — and available off the shelf at Home Depot.
The stage is a piece of perforated steel that I got from onlinemetals.com a few years ago. The tie-downs are what I always use: 3" 4-40 threaded rods and brass thumb nuts.
Fig.37: I wanted the face to be floating in a black void, so I taped down a piece of black velvet. I put a little bit of black velvet behind the face's eye holes, too, to hide the eye sockets. While the black looked inky in Dragon, when I rendered the final animation out of AfterEffects, I discovered a lot of color inconsistencies… Velvet was a good start, but I needed color keying to get a true black nothingness.
Fig.38: So finally the big question: How do you get rid of the seams in the mask?
I know, having attended a Laika presentation, that on Coraline they used Inferno as their software for seam removal. That software's alien to me, though.
Doing my own research, it looks like the magic bullet for this problem ought to be Adobe PhotoShop CS5's new tool "content aware fill," which the net has been buzzing about since its release in April. However, CS5 is incredibly expensive. Further research turned up that a FREE software called GIMP has a tool called "resynthesizer" that's supposed to do the very same trick. (Here's a useful comparison of "content aware fill" and "resythesizer.")
GIMP was originally written for Linux, but is available for Macs and Windows machines as well. Admittedly I'm not very proficient with the software yet, but still I was somewhat disappointed. Fixing each frame was laborious — and while better than the "smudge" tool alone, nonetheless created areas that stand out as blotchy when animated. (Out of curiosity, I'd like to try a demo version of CS5 at some point to see if it can do a better job.)
If these replacement faces were on a puppet that moves its head around a lot, maybe the smeared patches where seams have been removed would be less obvious. I don't know. On this project, though, I was able to employ a different method entirely, which worked quite well: I retouched just one face, and then used it as a clean plate — treating seam removal exactly like rig removal. This process still involves fixing frames one at a time… But simply erasing seams on the top layer in an image manipulation program is much, much simpler than having to blend, blur, and create pixels that additively cover up the unwanted lines.
So, conclusion? The replacement faces are a qualified success. They can look great when viewed from the front. Whether they can look good on a moving puppet, too, is unknown. The fabrication process is extremely laborious — easily eating up 100+ hours in the making. But once you have them, they're a great asset to have on hand. Right now, I'd say I'm 75% in favor of doing future puppet faces using the same method.
posted by sven | permalink | comments (3) | categories: stopmo
July 10, 2010
the beginning
by sven at 11:25 am
A new film!
The point of this was to do proof-of-concept for the new replacement face kit. It could have just been a test clip — but adding title/credits material let me do more with the idea and atmosphere.
I'm considering doing some longer films like this using the same face... So please let me know what you think of the look, eh?
(I'd also love to hear some feedback from folks with lipsync experience.)
posted by sven | permalink | comments (6) | categories: movies, stopmo
June 11, 2010
mold design (part 2)
by sven at 7:00 am
I want to do lipsynch using replacement faces. The idea is to have a set of ~12 masks that fit over a skull, which seats the puppet's eyes. Generic masks will be cast from resin, and then the mouths will be resculpted using either Super Sculpey or Magic Sculpt.
The resin will be cast from a 2-part silicone mold. The current iteration has several improvements over my last attempt:
- sculpt has better seal on mold bed
- to avoid entrapping bubbles, a "detail layer" of silicone is brushed onto the sculpt
- to conserve silicone, I've made a plaster "mother mold"
Fig.1: For my last mold-making attempt, the sculpt and mold keys were seated on a piece of wax paper. This go around, I decided to seat the sculpt on a bed of clay, to get a better seal.
I tried using Kleen Klay. However, I felt this material was much too soft.
Fig.2: For my next try, I lay down a bed of Chavant NSP medium, which is much firmer. I could then use Kleen Klay as a sealant without marring either the sculpt or the bed.
An incidental note about nomenclature… Both Kleen Klay and Chavant are types of oil-based modeling clay. I've been wondering for a while what the general term is for this stuff: "plasticene" or "plastilina"? Turns out the answer is neither. Both those words are genericized brand names — like how "Kleenex" is often used to refer to facial tissue in general. (reference)
Fig.3: How did I get the Chavant to be so nice and flat? I sent it through a pasta roller.
Polymer clay hardly sticks at all; Chavant leaves a bit of a film on the roller, which causes it to begin sticking to itself. I fixed a few minor defects in the surface by using a brayer.
(I also tried using a butane micro-torch to melt the surface of the clay… But then I had to wait a long while for it to cool again. More trouble than it's worth — wouldn't do that again.)
Fig.4: As with my last mold, the walls are made of 1.5" wide strips of repurposed foam core. I didn't cut the walls as long as before, though. Sealing the walls with hot glue was easier if the walls didn't hang out over the edges of the wooden base.
A note on cutting foamcore: box cutters work better than X-acto blades. Because the box cutter has a wider blade, it's more inclined to travel in a straight line.
Fig.5: I mixed up a small batch of silicone base, catalyst, and thinner. I applied the silicone mix to the sculpt using a disposable "acid brush." After watching a few videos online, I picked up that the trick to doing a "detail layer" like this is that you dab with the ends of the bristles, rather than painting with strokes.
I baked the silicone at 170 F for about 90 minutes to cure the silicone extra fast — then I put it in the freezer to re-congeal the clay. The oven temperature was low enough that neither the hot glue nor the foamcore seem to have melted. Happily, the silicone also seems to cure faster than the clay can liquify.
Even so, I kept the kitchen door wide open and stayed out of the room during this part of the process. I want to minimize the number of things that can possibly release fumes when warmed. I was surprised to discover that MDF gets smelly when heated. For the second half of the mold, I made a cardboard tray, which was better.
I believe I have a better alternative to using foam core for mold walls, too… The next time I make a mold, the walls will be made out of Legos!
Fig.6: The cured silicone "detail layer" is fairly floppy. To give it some support, I created a "mother mold" by pouring UltraCal 30 plaster into the box.
Fig.7: Here's the mold-in-progress after I've removed the foamcore walls. I really dig the layers of different colors!
Fig.8: The silicone pulls away from the plaster effortlessly. The mother mold bears the lumpy impression of the silicone. The lumpiness is enough to register the two parts together.
Fig.9: The sculpt came away from the silicone cleanly, and the detail layer has no bubbles. Awesome!
Fig.10: It's not a major flaw, but I was dismayed to discover that the acid brush left stippling in the sculpt. Apparently it's important to use a brush with really soft bristles. (Freezing the sculpt could also help protect it against brush marks.)
Fig.11: When I held the silicone up to a light, I discovered that there were several thin spots. The mold is useable — but I would have been smart to go in and apply a second layer of silicone on high areas of the sculpt to ensure adequate thickness.
[Now that I've done some castings in this mold, I'm noticing that the mold buckles a little at the thin spots… Acceptable but avoidable imperfections.]
Fig.12: This is 2-part mold. Side A is done — now to make side B.
I sculpted what will be the interior side of the puppet mask using Super Sculpey. I chose it largely for where it falls on the soft/firm continuum… But I'm not so sure it was the best choice. When I put it in the oven, it didn't get fully hard — but it did cure enough so that I won't be able to re-use the material.
The vertical rods at the top and bottom are to be sprues, where excess resin can escape. If this were a simple mask, just one sprue would be necessary… But I'm actually going to wind up doing the forehead and lower face as separate pieces. More about that later!
The trapezoidal blocks on either side will create open spaces that make it easier to pry the two mold halves apart. The four little dots will hold 1/8"x1/16" magnets, that allow me to attach the mask to the back of the puppet's head.
Fig.13: Once again I build a mold box. This time the walls are 3" tall. Cracks are sealed up with that ultra-soft Kleen Klay.
Fig.14: Again, brushing in a layer of silicone, using a dabbing motion to avoid creating bubbles. This time I used a soft-bristled art brush. Silicone destroys the brush — but I found ones being sold for 25¢ apiece at I've Been Framed (4950 SE Foster Rd), so not too big a loss.
Fig.15: This second layer of silicone also needs a plaster mother mold.
Fig.16: Opening the completed mold, I found that the Super Sculpey got partially cured in the oven. No big loss… But it wouldn't have been an issue if I were more patient and let the silicone cure at room temp for 6 hours.
Hypothetically, you could press Sculpey into the silicone mold and then bake it. Silicone tends to be quite heat resistant, so I'm pretty sure it could keep its integrity at the 275 F required for a full polymer clay cure… But I see no advantage at present. (Perhaps a less toxic solution than resin?)
Fig.17: OK! Here's the completed mold all cleaned up. Time to pour some resin!
Fig.18: The resin I'm using has a 1:1 ratio of part A & part B, measured by volume. I got these paper measuring cups at the same store where I bought the resin — TAP Plastics. Using 15 ml of each component is about enough to make a full mask with minimal overflow.
Fig.19: Safety first! When working with resin, you want impermeable gloves. I've got nitrile — I'm looking into butyl, which may have reusable options. Latex will not do — resin penetrates it.
Splash goggles. Long-sleeved shirt. And a respirator that has cartridges rated for organic vapors. I recommend 3M brand respirators. They're comfortable for day-long use — and these things only protect you if you actually wear them. If you go with 3M, the model no. 6001 cartridges are what you want.
* (Firefly reference. Shiny, eh?)
Fig.20: To get a good casting, there needs to be a little bit of overflow, which exits the mold through the sprues. For my first few castings, I laid down scrap paper on my desk to catch the overflow. Later on I refined my work area, covering a steel tray with sheets of wax paper.
Giving the resin 60 minutes to cure is ideal — but I found I could get away with demolding at 30 minutes. With about 15 minutes to clean up the mold and make another batch of resin, it looks like I can make one part approximately every 45 minutes.
Fig.21: Having thin layers of silicone that fit inside plaster mother molds makes it very easy to remove the resin castings. They just pop out. The flashing can be snapped off, or cleaned off more carefully with an X-acto knife.
However, I do recommend waiting a while before carving the resin. When you first de-mold, the resin is still soft, and it will likely distort from the pressure of your grip.
Fig.22: After doing a few pours, I've begun to recognize the areas that are most likely to capture air bubbles… The lips, the nose. So long as I pour carefully, it's not an issue. And if I'm nervous, I can just gently poke around in the area with a toothpick to break any hidden bubbles.
Fig.23: Comparing the Sculpey and Resin masks, you have to remember that the sculpt had to be modified before making the new mold… And the Sculpey's been painted, with makes it look better at this point.
The process of making a 2-part silicone mold is a great deal more time consuming than a simple plaster press mold. However, I feel much more confident that the masks I make will be identical in shape, and the mold is surviving the wear and tear of castings much better. So, in terms of my goals, I'd say the project was a success.
Next: Making a batch of generic masks and modifying them with different mouth shapes. Sorry folks, this may take a while…
posted by sven | permalink | comments (7) | categories: stopmo
June 10, 2010
mold design (part 1)
by sven at 4:14 pm
I'm back at work on creating replacement faces for the "Howard" puppet.
I've abandoned pressing Super Sculpey into an UltraCal 30 plaster mold. Getting the Sculpey out of the mold without distortion wasn't working out so well. And the plaster mold was beginning to lose fine detail.
Oh well. The press mold idea was always intended as a stepping stone on my way to something better: making resin castings from a silicone mold.
Fig.1: Here's a reminder of what Howard looked like when the Sculpey casting was fully painted. Doing resin castings from a silicone mold should allow me to replicate the original sculpt even more precisely.
Fig.2: The original Howard sculpt was made from Chavant NSP medium. It cracked when coming out of the plaster mold, but was otherwise in pretty good condition. Before making a new silicone mold, some repair and resculpting is called for.
Fig.3: The newly repaired sculpt isn't exactly the same as the original, but it's very close. There were a few areas that I reworked... And I also made the surface much more smooth.
I tried a trick I read about on pro sculptor Dave Pressler's blog, where you use a butane torch to melt the surface of the clay. Jury's still out on that one. [Note: I switched out the acetal plastic eyes for 3/8" stainless steel balls to fire-proof the sculpt.]
I also tried a trick I learned from a sculptor at Bent, where you use Brylcreem as a solvent. I like this one — it's nice that the solvent is a paste, rather than a fluid like alcohol or citrisolve. It's easier to control, and gives off less fumes.
Fig.4: The mold box was made from pieces of foam core that I got cheap from Scrap. Notice the way that the walls overlap one another — that makes it easy to get the things to line up well.
The sculpt is sitting on a piece of MDF (a type of particleboard) that's been wrapped in wax paper. The mold walls are set in place using hot glue. If the walls hang over the edges of the base, be sure to hot glue their undersides too, to avoid leaks there.
Acrylic hemispheres where taped into the mold to a act as mold keys.
Fig.5: I was dismayed to discover that my silicone is labeled as having a 6 month shelf life. I've had this current supply sitting around for 2 or 3 years.
The silicone base seemed even thicker than usual, and I think the working time was reduced. My first batch clotted up before I could do anything with it. A shame! Silicone is one of the more expensive materials in my workshop. :(
Fig.6: I ran a second batch of silicone, this time mixing it with silicone thinner. I was able to get a useable material this way — but it still wasn't thin enough to pour.
A big problem with silicone is that it traps bubbles. The pro solution is to put the material into a degasser (a vacuum chamber), which causes the bubbles to explode. Unfortunately, degassers begin at about $300.
However, there's a poor man's solution that I learned about from this excellent TAP Plastics video, where you cut a hole in your mixing cup… If you let the silicone pour from 3 feet up, it turns into a string on the way down, which breaks the bubbles. Pretty cool.
But, since my silicone was still too thick to pour, I just had to glop it into the mold as best as a could… Knowing full well It probably wouldn't result in a useable mold.
Fig.7: There are two kinds of catalyst you can use with this silicone: fast cure and regular cure. Fast cure takes 6 hours, regular takes 16. I HATE waiting between steps — so I went with fast cure.
Here's another really excellent trick. Stick your silicone in the oven at its lowest setting. (On mine, that's 170 F.) Curing is a chemical reaction, and chemical reactions can almost always be speeded up or slowed down by heating/cooling. By using the oven, I was able to get the silicone adequately cured in only 90 minutes.
But wait! As I learned the hard way on my last silicone mold, if you de-mold at this point, the Chavant will still be in a melted state. Take it out, and the sculpt is ruined — and it leaves a clay residue in the mold.
This time I was smart and put the mold in the freezer for a while before taking out the sculpt. Worked like a charm! The sculpt came out clean and undamaged!
Fig.8: As I feared, the silicone trapped lots of little bubbles. It looks like swiss cheese in there. Silicone also seeped underneath the mold keys an sculpt a little, creating a slight undercut, which is no good.
The mold is unusable. However, during the process of making this mold I had a little revelation.
I've always thought of mold-making as a matter of selecting one of the standard mold-making methods, and following it to the T. Now I realize that mold-making is actually a matter of design. Each mold you make is going to be somewhat unique, and requires an active application of intelligence and creativity.
With that insight in mind, I've decided to get good at making molds… Viewing mold-making as an artform unto itself.
This failure helped me come up with lots of improvements to build into the next mold design… Which is the subject of my next post.
posted by sven | permalink | comments (2) | categories: stopmo
June 2, 2010
mutate
by sven at 12:15 pm
Here's the new film: Mutate.
It was intended to be improv... But then the shape of a story emerged and I just had to see it out.
The project took about 75 hours to finish, over two non-consecutive weeks. Roughly:
- 38 hrs animating
- 26 hrs sound + editing
- 11 hrs set-up + clean up + learning Dragon
I prefer the look of puppets to clay — but clay does have its virtues. I had a blast sculpting those tongue and tentacle shapes. :)
posted by sven | permalink | comments (10) | categories: stopmo
June 1, 2010
stopmo in progress: mutate
by sven at 10:38 am
I'm almost done with a new stopmo film, "mutate." Just finishing up adding sound cues.
It can take months to to fabricate armatures, puppets, and sets for a polished stopmo film. I think it's important to keep your animator muscles warm in the meantime. So this project was a "quick" improv. Like going out for a jog around the block while in training for the marathon.
Short jogs are a good way to try out new methods. During this project, a number of tech issues have taken the next evolutionary step forward:
Framegrabber: Dragon
I've finally purchased Dragon Stop Motion — and it's been a joy to work with. Head and toes above FrameThief, iStopMotion, and AnimAideXT.
Hi Def
I'm shooting Blu-Ray standard Hi Def (1920x1080 pixels) using my old Canon PowerShot G5 digital still camera. This is my first time using the 16:9 aspect ratio, which has (finally) emerged as the unified standard for both film and TV. None of the computers at our house can play HD files — but you can always shrink the master file down. What I'm doing is future-proofing my films so that they still have some value 5 years from now.
Camera mount: Manfrotto
This is my first time using a Manfrotto 410 geared head to mount the camera. I'm a little troubled that you can't lock it into position... But its precision has allowed perfect recovery from a significant camera bump.
Shooting upside down
While shooting her film "Little Theatres," Stephanie Dudley has hung her camera upside down to get some tricky shots. An epiphany! There's no camera tripod to kick when the camera hangs from above! So much elbow room is freed up, I'm only ever going to use a tripod again if I absolutely must. [Incidentally, Dragon, makes flipping frames a breeze.]
I should comment on a few of the tricks I'm repeating from previous projects...
Modular stage design
Pros build their animation tables from the ground up. For my home set-up, it's worked well to build up from a 2'x4' folding table. I've got several reusable lighting pylons that attach to the table with C-clamps. (You can never have too many C-clamps!) For this project, there were no tie-downs — so I didn't need a raised stage — I could work directly on the table top. But for future projects, I can quickly set up a raised stage by clamping horizontal struts onto the pylons, which then support the stage floor. I'm really happy with this fast, versatile approach.
Field of vision
After locking the camera in place, I find it very useful to tape off the boundaries of what the lens can see. This avoids wasting fabrication time on stuff that won't be in frame.
[I've gone a step farther, too. I know that the G5's maximum angle of view is 54.4º. After doing some basic trig, I realized this means the distance of the camera from the backdrop is very nearly equal to the width of the backdrop. This 1:1 ratio is extremely useful for estimating how much studio space I need for different set designs. Anyone interested in learning more about that math?]
Lighting
I've got two GE Crystal Clear 200 watt bulbs pointed at the ceiling. Each puts out 3980 lumens — which is massive. The bulbs are commonly available at department stores and Home Depot. Bouncing the light off the ceiling approximates noontime on a slightly overcast day. Bouncing diffuses the light, to avoid any hard shadows. Not very dramatic — but handy if you just need a flat, cartoony look.
OK, that's enough for now. I hope to have the finished film posted sometime this week.
posted by sven | permalink | comments (3) | categories: stopmo
April 15, 2010
the whisperer in darkness - big news!
by sven at 10:55 pm
Two big news items. First, there's a new trailer for The Whisperer in Darkness:
Second: I've just finished a top secret project for the H.P. Lovecraft Historical Society!
I've got some beautiful photos — but can't share them yet. For now, all I can do is tease you with process pics, impressions and interesting numbers…
The HPLHS contacted me on May 5, 2009 about making armatures for Whisperer. On Apr 5 — eleven months later to the day — they opened a box I'd sent them.
Between those dates, I put in 675 hours of hardcore research, development, and fabrication.
The first email described what they needed as "fiendishly complex." The message upon receipt of my package described the contents as "a thing of terrifying beauty."
I compiled some statistics before sending off this armature. It's assembled from 239 parts:
- 101 screws
- 132 hand-crafted parts
- 6 wire segments
And it has a total of 63 joints:
- 41 hinges
- 16 ball joints
- 6 swivels
The strangest part for me, experientially, was seeing that galaxy of atoms finally condense down into a single object.
It was unnerving putting 11 months of my life into a box and entrusting it to the US Postal Service. In the first day or so after letting go of it, my thoughts were mostly consumed with how I could make the joints better, worrying that they could somehow not be up to snuff. But after the glowing receipt — and catching some sleep — I hit a state of giddy elation. …Kind of like I've won.
And now? Doing laundry or dishes — doing anything other than machining — it just seems like the most wonderful treat!
posted by sven | permalink | comments (9) | categories: stopmo
