Work in progress: Four-part intersections bowl

Since I’m currently working on folding a multi-piece model, I decided to post some photos in progress to show how the design and folding process all come together. This piece will essentially be a continuation of my Intersections series from last spring. The design process started in November with a sketch of a possible top view of a model. I sketched quite a few other ideas that day, including a few I’ve already folded and some I’m still planning to fold.

Initial sketch

Initial sketch

Since I’ve folded quite a few pieces in this series already, I essentially knew from the time I started sketching how I would approach folding these pieces. The one part I needed to double-check was folding the concave 90-degree turn in the middle two pieces. I did a test-fold from a post-it note to make sure I knew how much extra paper I needed to make the turn.

Test fold of a 90-degree turn

Test fold of a 90-degree turn

After that, it was time to start actually designing. I made a detailed sketch and worked out all the math so I could cut the paper into the correct size rectangles. If you look closely, you’ll see that I use a combination of inches and centimeters. Perhaps surprisingly, that actually simplifies some of the math compared to just using one set of units. I can calculate most of the dimensions using the same sort of math I explained in my tutorial on designing curved-crease models.

Full sketch, version 1

Full sketch, version 1

Here are the primary tools I use: a ruler (I actually have five rulers of different lengths and use all of them on a regular basis), a sharp tool for scoring the paper, a cardstock template that I use to score the curved folds (I cut a new template for each model), and a ball of used tape (this is how much tape I’ve gone through since mid-December).

Tools of the trade

Tools of the trade

I decided to fold the tallest piece from my design first and started scoring the straight folds and folding along the scored lines.

Piece 1, version 1: Unfolded

Piece 1, version 1: Unfolded

The base folded exactly how I had planned and how I’ve folded many similar designs.

Piece 1, version 1: Partly folded base

Piece 1, version 1: Partly folded base

Piece 1, version 1: Folded base (inside view)

Piece 1, version 1: Folded base (inside view)

However, I ran into problems when I got to the top half of the vase. I had forgotten that having the top of the vase flare out would require extra paper, so there wasn’t enough paper there to make things work correctly. Since I added extra creases trying to figure out how to fold the top, there was no way to salvage that piece of paper and turn it into a cleanly folded final piece.

Piece 1, version 1: Folded top

Piece 1, version 1: Folded top

So because I had to start over with the folding, I decided to re-design in such a way that the vase didn’t flare out at the top. The new shape is very reminiscent of one of my first pieces in the series, folded just over a year ago. I tweaked some of the other dimensions as well. For these designs, I have to be careful that the radius never gets smaller than 1/3 of the radius at the widest point and that the radius at the base is at least 1/2 of the largest radius. Otherwise, the folding gets much more complicated.

Full sketch, version 2

Full sketch, version 2

This time, the folding worked much better. If you look closely, you can see that the piece still has a lot of tape from gluing and wet-folding; I’ll go back and remove that before taking a picture of the final design. There’s also a popsicle stick taped to the top edge to hold it straight while the paper dries.

Piece 1: View of curved side

Piece 1: View of curved side

Piece 1: View of flat sides

Piece 1: View of flat sides

I’ve also folded the second piece, which has an L-shape. I ran into a few problems here getting all the layers of paper to fit inside correctly near the base, but fortunately I was able to make it work with a few extra folds.

Piece 2: Side view

Piece 2: Side view

Piece 2: Top view

Piece 2: Top view

The two pieces fit together nicely. They look better standing with a small gap in between; if I try to put them too close together, the little bulges and curves in the paper become too obvious. Of course, leaving a gap was part of my original sketch. So far, I’m happy with how these pieces have turned out.

Pieces 1 and 2

Pieces 1 and 2

I’m working on the third piece now, and hopefully I’ll have time to fold the fourth soon. I’m looking forward to seeing how the finished piece looks!

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