Three dimensional printers are around but quite expensive. This is an idea for a cheap DIY approximation of one (improvements welcome).

This system is comprised of polyurethane foam and a manually adjustable "mesh" that the user adjusts with "height map" parameters output from a specialized CAD program (or plug-in).

The "die" consists of adjustable pegs arranged in a square pattern on a board each of which are attached to a single flexible rubber sheet coated in a non-stick material (or a chain mail like mesh).

For example, to get a single "spike" rendered in 3D, the user would receive output that resembles:

9 9 9 9
9 1 1 9
9 1 1 9
9 9 9 9

He would raise the spikes at the edges of the 4x4 square to "9", lower the spikes in the center to "1", and create the polyurethane material by mixing its components (usually available in tubes labeled "A" and "B" that you mix to create the foaming polymer). He would then pour the material in this flexible die, wipe off the excess, and wait for it to set.

In reality, of course, the number of pegs would be larger (such as 32x32 or 64x64.
-- cowtamer, Jul 17 2008

You can use < br> sans space for a single line break to format as below:

9999
9119
9119
9999

As for the idea, the die creation method sounds extremely crude, but might work well enough for simple, potatoe-like geometries.
-- Texticle, Jul 17 2008


Texticle, thanks for the suggestion.

I was thinking perhaps an articulated sheet made up of multiple expandable polygons might do better than a rubber sheet. (I'm thinking of a sheet composed of flat, rectangular sections that are hinged to each other. Each rectangular unit would have to be deformable only in its own plane, thus allowing something other than Mr. Potatohead clones to be rendered).
-- cowtamer, Jul 18 2008



random, halfbakery