Information about our unique techniques and processes we have developed for our artwork
Ema Tanigaki’s Curved Folding Process

or the basics of Curved Folding by Planar Reflection

Ema's process for folding metal sculpture is based on the theoretical process of folding based on the academic paper "Interactive Design of Planar Curved Folding by Reflection" by J. Mitani and T. Igarashi.
The first step is to create a virtual curved sheet in a Computer Aided Design (CAD) program. Ema is currently using Fusion 360. This illustration is a screen capture from this software program.

As the process title implies, the second step is to create a plane (a two dimensional virtual surface) In this illustration indicated by the blue surface, intersecting the curved sheet

Thirdly the curved sheet is reflected using the same plane. One can see on this illustration that the new reflected metal is the mirror image of the original curved metal. (the reflection plane is yellow-orange in this image)

If you remove the original curved surface that was reflected, one can see that we have created a virtual folded form.
This type of fold is "developable" which means the sheet can be unfolded back into a flat sheet. This is the difference from other methods of metal forming which deforms the metal so it cannot be reverted to its original flat sheet form.

The same process shown in the previous slides but viewed from a different angle. Step one intersect the curved metal with a plane.
Developable folds are the basis for the traditional Japanese art/craft of Origami, the folding of paper.

Step two: reflect the curved metal using the plane as the reflective surface.
This folding method has allowed Ema to create sculptures on a larger scale as she does not have to be able to make forms to press or hammer into/onto to make specific curves. Since Ema is a petite human her arm span is very limited and has until now limited the scale of her work.

The finished virtual fold with the plane visible

The finished virtual fold.
Using multiple planes at differing angles, more complex shapes can be designed.

This is an image of a sculptural form created using this method. The translation from a virtual design to an sculpture that exists in the real world is the process that Ema has developed.
This work uses perforated metal. One can see that this form is a developable fold because the circular holes in the metal are not deformed.

curved sheet -
curved sheet with plane -
curved sheet with first reflected fold


second reflected fold
third reflected fold


fourth reflected fold
fifth reflected fold - final design



The challenges of creating new processes keeps us innovating. Michalangelo developed new methods to enlarge small figures into towering marble forms, thus creating "David". Ema does not claim to be a new Michalangelo, but the drive to innovate is shared.
This is the theory of folding. However the creation of sculpture goes beyond just mathematical theory into artistic expression.
A slideshow tutorial on the process of designing curved folds in sheet metals