
Novel 3D printing method blossoms from botanical inspiration - bootload
http://wyss.harvard.edu/viewpressrelease/239
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puppers
The name "4D printing" is misleading. Though, I'm not sure what I was
expecting anyway.

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jobigoud
An actual 4D printer could be trivial though. Just like the 3D printer
discretize the height in several layers, the 4D printer would slice the fourth
dimension in several hyper-layers and print a 3D object for each slice. We
already have the software to create 3D slices out of 4D objects.

The trick will be to reassemble the slices into a 4D object :-)

Just looking at these cross sections could be interesting. Also printing the
same object at different resolutions along the fourth dimension could be
insightful.

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dekhn
There's more than one dimension- any real parameter is considered a dimension
in this context.

In this case, as the PR specifically says, the fourth dimension is time: they
are encoding a temporal path within the object.

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scribu
It's amazing that all plant behavior is actually governed by chemical
reactions applied to "cleverly" constructed structures.

I suppose the next step would be desinging a structure that responds
independently to two or more types of stimuli at the same time.

For example, a leaf-like object that bends in the Y direction in response to
humidity and in the Z direction in response to light.

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thaumasiotes
> It's amazing that all plant behavior is actually governed by chemical
> reactions applied to "cleverly" constructed structures.

Unless I'm missing something, this describes all behavior above the subatomic
level, plant or otherwise.

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scribu
Animal behavior is governed by brain activity, which is electrical. (Yes,
there is some chemistry involved too, but it's secondary).

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nxzero
Pretty sure that printing a 2D or 3D model that is responsive to external
changes is not a new thing; recall a material that takes two forms based on an
electric charge.

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sp332
"Novel method" doesn't mean something similar has never been done, it means it
has never been done this way.

 _By aligning cellulose fibrils during printing, the hydrogel composite ink is
encoded with anisotropic swelling and stiffness, which can be patterned to
produce intricate shape changes. The anisotropic nature of the cellulose
fibrils gives rise to varied directional properties that can be predicted and
controlled._

