Origami Helmeted Hornbill

Helmeted hornbill is a huge hornbill with round casque, featherless throat, spiky hair, and two very long tail feathers. 

Unlike other hornbills, its casque is solid (not hollow) and for some reason some people like it. It is sought as valuable item just like elephant's tusk. Overhunting has driven them to be critically endangered.

This is the most challenging subject that I've attempted so far.

Design

The goal of the design is to express 4 essential features:

1. Color changed beak
2. Color changed and pleated neck
3. Spiky hair
4. Very long tail feather

There is one additional feature: color changed legs and complete toes. I don't think it's important since the bird's main feature is in the head. So having them would be optional.

Given the need for color change, I decided not to design the bird in flying position since color leak on the open wings would be troublesome. So the bird will be in perching position.

I drafted the idea of creating base like this:

Let's break it down:

1. Upper part of the head will cover upper beak, casque, hair, and eyes. The beak would need extra paper for level shifting to make casque. That flap, along with the eye flaps would need to be in the edge or corner for color change. The hair can be expressed with numerous small middle flaps to be spread like my helicoprion's teeth. Eye flaps can also come from lower part of the head, it doesn't really matter.
2. Lower part of the head will cover lower beak and pleated neck. Both require color change. If I use flap distribution to make the pleated neck, I can just express it as just one long flap. It's like Kamiya's winged kirin.
3. Wings/body can be expressed by single wide flap. Just like typical perching bird origami.
4. Legs should be trivial. Aim for color change and complete toes if possible.
5. Tail will be very long, so it better be made using corner flap.

Splitting the head into two independent flaps would simplify the color change and structures I needed to represent the funky head. Both parts of the head and tail would use 3 long flaps, and body plus legs can use 3 shorter flaps. This gave me the idea of using bird base with one corner getting pleated to make legs.

Wing flap would be somewhere in the middle.

The idea of using asymmetric layout is to use the corners for color changed and long flaps. Especially on the tail and legs area. It is clear that this layout allows better efficiency. How would the entire crease pattern look like? No idea. I'll need to test stuff here and there to make it work.

I gave it a test fold on a plain bird base just as a prove of concept. It kind of works. Now I just need to figure out how to express the features on the head. The plan:

The next few days, I made numerous attempts by putting strip graft in the diagonals, or making a border graft. Nothing works as I would hope for. The problem is the difficulty of aligning the upper and lower beak. I began to explore different layouts to make it happen.

About 2 weeks had passed. None of my test folds were promising. I had a good feeling about my initial layout so I tried that again. Focus on the lower head and forget everything else. This time using border graft and I decided to swap the lower beak and pleated neck position. This allowed the neck pleat to be folded from the corner so it is much easier to do. The legs can be made using point splitting. In the end it's a bird base with point split again, a recurring theme in my designs. Things started to get brighter here.

Upper left quadrant is the lower head part. In the test fold, I made it into a fish base.

I doubled the graft size to make longer flap for neck pleat. A level shifter is added to prevent self intersection (found during test fold). Larger border graft made the other head part and tail longer, but not the legs. There's also an unused corner that became longer.

Area surrounded by yellow border shows the area for legs.
Circle shows the length of that flap. The large quarter circle in the corner is a wasted space.

I remember folding Katsuta's griffin and Shuki's greater kudu. On their design, the hind legs are extended using graft that travels diagonally. This is perfect chance to use the same structure.

Longer legs and less wasted space.

Longer neck-pleat flap, legs and tail.

Now moving to the upper part of the head. There's no way I can make the spiky hair using an array of middle flaps in the main diagonal like my helicoprion's teeth. So I thought to lay them in the arc of the flap. This idea is similar with Kamiya's praying mantis arm spikes. The one touching paper edges would be used as color changed eyes. I can use seamless eye I used on peacock spider. Finally the upper beak that contains the casque can be made by reverse folds. The crease pattern is found purely by fiddling on the paper.

Head test fold.

Finally the tail. Nothing fancy on it. I just want to make it uniform in width so I shifted the squash all the way to the top as much as possible. I learned this when folding Shuki's brachiosaurus.

All the parts put together.

With all parts done, I made a test fold using Japanese foil. It works as I would hope.

I proceed to make the final fold using double tissue. Once done, I felt something is off. At the very least I think I want to make complete toes.

The people in Origami Dan gave me the following feedback:

1. The eyes are too big. Big eyes made this model cartoonish, that's what made me felt something is off. Actually some suggested to keep that big eyes. 
2. Need feather on the body to suggest a folded wing.
3. Body is too small.
4. Make the pleated neck resemble a throat rather than a plumage.
5. Color change the legs.

Slightly off topic, I am fascinated by Origami Pro 6 book. There's a toucan model on that book by Han Ji Woo, and I aim to mimic that style. Therefore I decided to make the eyes smaller.

For problem 2, I can just pleat one of the edge in the middle flap to suggest wing.

Problem 3 is solved by making the neck shorter which in turns making the body longer. Also by making eyes smaller, the beak would appear to be larger and improved the overall proportion balance.

Problem 4 can be solved by further curving the pleat towards the body. It's just a matter of shaping and fortunately not a structural issue.

Finally on to the legs. A straightforward way to add toes is by lining them on the pleat. While it can easily produce the accurate number of toes, the length is off. They will be too short.

I checked the circle river packing happening there and look for a room to improve it. Apparently I can snug one toe to the useless pleat area. The toe parts resemble half frog base.

Notice the larger circle, highlighting longer toes.

There are 2 toes on the middle flap. I don't think I can color change them and will just fold it they way it is now. The plan was to wait for weekend to come and make the final fold. However, one day I took a nap after exhausting work and dreamed about unwrapping the entire leg section to make a color change. Once woke up I grabbed the test fold and experimented on it. It's not exactly unwrapping the entire leg section. Just unsink two of the pleats and it is sufficient to make color changed legs. Here's the concept demonstrated on earlier version:

Unsink the marked area for color changed legs. Same for the rabbit ear in the corner.

Apply the same technique on the fully toed version, and we'll get the final version of this design.

Fold

The final fold uses 38 cm double tissue. Collapse started from the upper part of the head, then lower part, legs (as single long flap), and finally tail. Then the single long flap for leg can be split like usual point splitting on bird base, then form the diagonal pleat. Refer to Katsuta's griffin if you want to know the sequence. Lastly, unsink as explained before and form the toes.

Just a note for reader and my future self (if I ever to fold this again), here is the sequence I used to collapse the head. Precrease the border graft first! 

Performing the leg unsink and collapsing the toes are the most difficult procedure. I was too lazy to find sequence to form the toes so I precreased almost everything and slowly collapse it from middle to out.

Once fully collapsed, it is important to rearrange the flaps on the lower part so it goes like leg - tail - leg rather than leg - leg - tail. The leg is quite thick and it would look funny if the tail came out from the right side of the right leg.

Below is some progress picture.

Through this model I learned to not be hasty. Sometimes spending some time away might give us inspiration to solve the existing problem (in this case, the leg color change). The model can be more interesting that way.