How to Solve Crease Patterns

Sorry for the Hiatus everybody, I was off on vacation in Indiana and had no internet access. I folded a lot, though, so if nothing goes wrong I’ll come out with a few posts very quickly. And before I forget, Happy Holidays to you all!

Today I tried something I’ve never really done before-- designing a model by crease pattern, using module theory. For those of you that aren’t familiar with this method, I took a tree figure for my chosen subject (in this case a bull) and made a crease pattern for it using the same triangular modules that make up most of the classic bases (the bird, frog, and fish bases). I came up with this crease pattern:

The red line on both crease patterns is for reference. On the colored version, the red are the back legs, the dark red is the tail, the brown is the torso, the purple is the front legs, the blue is the neck, the light green is the horns, and the dark green is the eyes and snout. I’m sorry about my limited paint skills, the neck and torso rivers aren’t quite shaped like that; but I don’t have the time or patience to figure out how to do it right. They aren’t too far off anyway.

But anyway, once I had this figure composed, I realized it was not very easy to fold from crease pattern, and thus the teeming masses that I hope are reading this may have trouble doing so and get stuck (but not give up, right? eh?). So I decided to blog on how to collapse crease patterns, using this as an example. For a more detailed set of directions accompanied with pictures, look in the corresponding photo set on my Flickr page. I didn't add them here because I have dial-up, and that would take too much time. First, make as many of the bigger folds as you can. Here, you fold the diagonals first, then use the reference mark (made by folding the square in half here) and bisect the area between it and the diagonals; then make the next set of folds, matching the ends of those bisectors.

One thing you want to keep an eye out for is patterns you’ve seen before; for example, on the two corners on either side of the middle section, there is the crease pattern for a half bird base; so you can pleat the center part over to the side and fold the bird base all at once.

The head and tail sections can be creased by means of a number of mountain and valley folds; then comes the tricky part of collapsing the base. Here, start with the half-bird bases on the sides; then fold the torso flap up and collapse the lines for the middle of the base. For the head, you’ll have to make the bird base on the inside in between some layers; this is no easy feat, as you must hold the layers around it flat while folding it. However, once you finish that, the base is complete.

Next comes what I think is the hardest part: shaping and finishing. This often requires a lot of vague folds that have to be estimated; but the crux of the situation is, you must make the model look like the subject using various methods from the proverbial designer’s bag of tricks. I posted a full sequence of pictures on my Flickr page; look inside the set labeled “Crease Pattern Solution: Bull” and you should find enough pictures to help you finish it off. Essentially, what I did was reverse-fold the head section upward, position the horn and eye flaps, make a nose and eyes, and curve the horns; then I positioned the legs and folded some rather mediocre-looking hooves on the leg flaps (I’ll figure out some good ones eventually, but now’s not the time), and rabbit-eared to make the tail.

A few optional things that can be done are to lock the inside layers together, to hide the folds around the tail, use wet-folding to put some nice shaping folds on the back, head, and legs, etc. Also, the nose can be turned into a lower jaw instead, a la many of Montroll’s animals.

So there you go. If you’ve been following along, and have gotten stuck or don’t like the way it turned out, remember: folding from a crease pattern is one of the hardest things to do in origami, and it takes practice. If you’ve gotten really stuck, email me or leave a comment and I’ll try to help you.

Have fun, and get to work on some more crease patterns!

An Excercise in Modulation

John Montroll’s Starfish, from Animal Origami for the Enthusiast, has always been a favorite of mine; both because of the base that it employs (a five-sided preliminary fold) and because of the nice curving effect presented as a result of the folding process. I was playing with it a few days ago and noticed an interesting property: the crease pattern can be reduced to five side-triangles, as opposed to the customary four for a waterbomb base or preliminary fold. Upon reflection, I realize that this was quite obvious, but nonetheless, I was determined to do something with this model, to help me understand its structure and the process used to design it if not out of sheer curiosity. I shaded the finished base with a pencil, and then opened it out to see where these component triangles lay. Surprisingly enough, it was a logical arrangement on the outside of a pentagon, superimposed onto the framework of a square.
This whole experience, of course, provided an interesting mathematical puzzle: If this could be done from four to five points, then why not from five to six?
I played with it on paper for awhile, and this is what I came up with:

In case you haven’t guessed, the gray bits are unused paper on the edges, the green the collapsed paper in the center, and the blue is the actual triangles that make up the model itself.

I wouldn’t be surprised if somebody’s already done this before, but it’s a neat little exercise in modulation nonetheless. I also tried this for eight points, but it didn’t work out as cleanly; there was too much extra paper sitting in the middle of the model to look very good. The crease pattern, for those who are wondering, was essentially built off of a blintz fold.

Also, many thanks to Eileen Tan for putting me onto her RSS aggregator! If you don’t know about it already, I suggest checking it out; it saves you the time of having to check six or seven different blogs each day, and it follows lots of excellent blogs that I hope mine will someday equal. It’s at http://spinflipper.com/origami/feed.php.

Welcome, Fellow Paperfolders!

Hey there, teeming blogoshpere! It's yet another origami design/presentation blog! I've been folding casually for as long as I can remember, and more seriously for the past year or so. I've gotten to the point that I think a blog might be useful, as a personal journal if nothing else. Some of you may have seen me as a hudson on the origami forum, (http://www.thekhans.me.uk/forum), or as origami_madness on Flickr, although I've been considerably less than prolific on either one.

But anyway: as I said, this is an origami design/presentation blog, so I'm going to introduce one of the models that i've done recently. On the left is me wearing Jeremy Shafer's "Flasher Hat", from his book Origami to Astonish and Amuse (published by St. Martin's Press). I folded it out of 28 inch peice of green butcher paper, and it took about 8 hours; butcher paper probably wasn't the best choice... it's too hard to work with, for models that require a massive all-in-one collapse like this one.