The concept of using projection mapping to bring a mask to life has been haunting me for a while now. When I saw the low-poly masks by Wintercroft I knew that I had to try to pull it off this Halloween. I cant say that the execution is very elegant (bulky bike helmet boom with massive counter weight) but I think the result shows some potential: I made some random lady walk into a tree from rubber-necking, and won the costume contest at the local bar! My next iteration will probably include some form of lens to shorten the throw distance, I hope this will inspire some people to take it to the next level.

This is definitely not a last minute project nor is it one for people who get frustrated by failure. You need a lot of gear, not the least of which is the projector:

Battery powered projector with a video playback capability: Mine is a touchpico that I got from the original Indiegogo campaign. The price and quality are always improving but expect to pay 150$ minimum for something with an internal battery, playback capability and small form factor. examples from amazon
An old helmet: Mine was a bike helmet (light and stiff, but bulky and ugly)
4 foot length of aluminum angle bar (10$ from local hardware store)
A bolt and nut that will fit your projector mount
A template for the low-poly mask from Wintercroft; You can make your own with Pepakura and some skills (maybe next time for me)
A full size sheet of card paper, there is a limit of the thickness which will give you a nice clean crease and have some stiffness. The stuff from you dollar store is actually pretty good.
Duct tape, or invisible tape.
A white wig to cover the front of the helmet
A deep hooded costume (e.g. jedi robe)

For the cloud you will need the following items:

3 x 40 inch #1 foil balloons 18$ amazon
4' by 6' of quilt batting 10$ amazon
A length of LED lights with a battery pack 25$ amazon
Some packing tape, a strip of coroplast
A pole and stand (I used a fake bamboo pole and a small tripod, but it wasn't ideal)

Step 1: Low-Poly Mask

There are some really great low poly instructables available, but I wanted to leave the geometry for the experts this time around (I had enough technical hurdles to overcome). But if you are looking for inspiration please check out: kamibox.de's Big Head or Krumrey's deer mount; there is a specialized software called pepakura that I plan to add to my toolset eventually. So I took a shortcut, and purchased a template from Steve Wintercroft (very cool site with lots of mask templates). The steps for assembly are very similar regardless of the template, the photos are from an early attempt (3 in all).

Print the template onto the recommended paper size
Roughly cut out the paper being careful to not cut along folds or any of the templates
Glue the template onto the card paper (Corn Flakes box in this case) the nice side of the paper should be on the opposite side
Score the fold lines with a ball point pen, if you can find a pen with transparent ink you'll be able to preserve the lines indicating if it is a mountain or valley fold
Carefully cut out the card paper along the solid lines from the template.
Fold the card paper according to the line type on the template (mountain or valley).
Tape the pieces together. Wintercroft suggests taping on the outside with invisible tape, but I preferred to tape it from the inside with duct tape.

Step 2: Projector Mount Challenges

This was the most difficult part of the project. I went through many versions before settling on the design you see here; there are a few other things I would like to try (adding a lens to shorten the throw). Some of the things that I tried included using a mirror to keep the weight more centered, the projector oriented vertically and horizontally.

Challenge: Stiffness and Predictability

The ultimate goal is to have a fixed and predictable geometry so the the projection can fit with the mask's polygons under real world situations. The slightest change in angle between the projector and mask is immediately obvious, and is detrimental to the effect. This was achieved by fixing an aluminium angle bar in slots sawed in an old bike helmet. Tie-wraps were used to keep everything in place. It's not pretty, but it worked.

Challenge: Weight Distribution

Another major challenge is the distance of the projector from the mask: the larger the projection area, the further you have to place the projector and the more downward force it creates at the front of the headset. After a few trials, I wound up adding a lead-acid battery to the back of the helmet as a counterweight. The size and weight of the resulting headgear balanced but cumbersome and the rest of the costume was adapted to hide this.

Future technology should provide solutions: smaller projectors and better batteries, along with short throw lenses will keep the projector light and close to your face.

Challenge: Projection Geometry

You can't have the projector directly in front of the mask or else you can't talk with anyone without smacking them in the face (I did that a few time anyway); the projector will also be in the line of sight of any viewers. To solve this issue, I made the projector boom angle up at about 15 degrees; this reduced my strikes to a minimum (3 lamp strikes and a few bonks to the heads of my friends). This angle also increases the projection coverage in the vertical direction: think of how a spotlight beam grows as you angle it from straight down (tight circle) to an angle subparallel to the target surface (very elongate ellipse). This was beneficial for me because the mask was relatively long, so I could put the projector closer to the mask and help deal the with the other challenges discussed above. A drawback of setting the projector at an angle, is that the down-facing polygons will not get any light. I didn't care too much in my case because it gave an ominous look: dark below the brow ridge.

Step 3: Attaching the Angle Bar to the Helmet

I gave a lot of thought to head mount options, and reluctantly settled on an old bike helmet. It has the advantage of being light and stiff, on the other hand it is relatively bulky and instantly recognizable as a bike helmet. I realize that the steps are not very clear, given the geometrical complexity, please look at the photos.

Figure out your geometry; you won't get 3 tries so measure twice and cut once
I used a wood saw to cut a slot along the side of the helmet at the depth of the angle bar
Drill a hole near the end of the angle bar and insert a bolt that will fit the mount on your projector
Slide the angle bar into the slot and fasten it with a couple of tie wraps
Attach the projector to the angle bar and slide the angle bar until you get the optimal mask coverage (just wide enough to cover the mask). You can tap the mask temporarily, the final installation was made with short nails pushed through the top of the mask into the foam of the helmet.
Once you have established the optimal boom length, take off your projector and set it aside.
I trimmed the back of the helmet with a saw, you may not have to, depending on your helmet
Cut a notch in the horizontal side of the angle bar in line with back of the helmet
Fold the angle bar so that it now touches the back of the helmet at a right angle
Mark the back of the helmet where the angle bar touches it
Pull the angle bar back along the slot to free up the back of the helmet to saw a new slot for the back of the angle bar
Pull the angle bar back into place so that it fits in both slots and apply tie-wraps to the back of the helmet
Put the projector back on, realize that it is way to heavy in the front and find something heavy to attach to the back as a counterweight (using tie-wrap of course!).

I am sure someone will come up with a more elegant solution to mount the projector, please comment below.

Step 4: Projection Mapping With HeavyM

I don't want to get into too much detail here. There are several videos available that explain the process (including the intro video and my cake walk-through) and the software is getting a major overhaul in the next few weeks. The official tutorials are at the link below, this is how I learnt how to use this relatively easy software.

http://www.heavym.net/en/howtouseheavym/

Step 5: Zeus' Cloud

Zeus needs a thundercloud to go along with his lightning bolt. I've been wanting to attempt the amazingly realistic examples like this or this; admittedly my attempt was not as convincing, but still very eye catching and relatively mobile. The initial concept was to have the helium balloon have sufficient buoyancy to hold up the quilt batting and the lights. I had purchased some more lightweight LED lights, but the impact of the changing colors from a separate and heavier strip outweighed the effect of a self-floating cloud, so I went for a cloud on a pedestal instead. I hindsight I wouldn't have needed helium fill in the balloons, but the girls are having fun with them so not all is lost.

I used a steel pole to hold up the cloud, but I wanted it to be tethered to a tripod, so I welded a bolt onto the base of the pole that could be threaded onto the tripod.
I drilled a hole near the base of the pole to thread the cables that I used to connect the battery pack to the LED controller.
I connected and soldered the 4 connections.
I peeled a part the batting to make it thinner and more irregular in texture.
I taped the bottom two cylindrical balloons together.
I inserted the pole through the center of the batting and between the two balloons.
I cut a strip of coroplast and taped it to the top of the pole to protect the balloons and provide a little more control when turning or pulling the cloud through a crowd or doorway.
I taped the third balloon onto the first two with a slight offset to have a more interesting geometry.
I taped the LED strip in spots letting it hang like a garland around the edge and underneath the balloons
I wrapped the balloons with the batting and used some white thread to hold it closed and to make some folds. These folds give a much more cloud-like dimension to the project, but I found that the result was not as convincing as the examples mentioned above. In fact the DJ at the bar I went to for Halloween called me Cocoon Man...

Step 6: Zeus' Bandolier and Lightning Bolt

I needed to use my Moroccan djellaba (North African outerwear very similar to Jedi robes) for its deep hood to cover the massive head gear. However this wasn't very "Zeusy" and lacked detail. So I bought a metal patterned belt from Value Village and spray painted it yellow to match my bolt. I lengthened it with electrical wire to enable its use as a Bandolier.

I have a separate instructable for the Lightening Bolt.

Step 7: What's Next?

This was fun proof of concept and it was very satisfying build. I cant say that the end result was really elegant or comfortable, but it did make some lady on the street walk into a tree while gawking at me. Please let me know if you have any ideas or you've made something similar, I would be keen to see how this concept evolves!