3D Printing Objects With Caustics | Two Minute Papers #38

What are caustics? A caustic is a beautiful phenomenon in nature where curved surfaces reflect or refract light, thereby concentrating it to a relatively small area. This technique makes it possible to essentially imagine any kind of caustic pattern, for instance, this brain pattern, and it will create the model that will cast caustics that look exactly like that. It also works with sunlight, and you can also choose different colors for your caustics. The authors found their simulations to be in good agreement with reality, therefore the desired caustic patterns can be fabricated faithfully.

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The paper "High-contrast Computational Caustic Design" is available here:

The full Rendering course at the TU Wien is available here:

More results from this project are available here:

Image credits (all CC-BY):

Károly Zsolnai-Fehér's links:

[Kram]

Two things:
- at least currently, the shapes in question are not 3D-printed but rather milled from chunks of plexiglas
- as a result, I'm almost 100% certain (it wasn't entirely clear in their own video on the topic) that the colored ring example was a CG demonstration and not an actual real-life model. Their actual sculptures are all fully clear for now.

That being said, both of these things, I'm certain, could happen at least eventually. Transparent plastics for solid sculptures should be easy enough to 3D-print. Multicolored versions should be tougher though.

[tariqulislam]

Wow. This is
I never knew of this phenomenon. This is awesome....

[huntrezzjanos]

omg just coming across this karoly. ez mar egy hihetetlenul jo dolog omg i really want to build my own caustic calculated object!! going to go watch ur lecture now. been watchng ur vids for awhile now ur def one of the best youtubers

[davidmcsween]

Could you encode more than one caustic result depending on the angle of light? Like the shadows cast from varying profiles around an object. It would make for a great advertising display object that would change as the sunlight traversed the sky. Also is there anyway to modify a surface dynamically (like water does) to animate the caustic result? Any actuators would interfere with light transport I guess. Perhaps sonic standing waves propagated over a small surface could be projected onto a larger area?

[Kram]

That's really amazing!
This same technique would be nice for CG too.
Here is an insane idea: Super stress test your favourite rendering engine by just setting up a point- or parallel (sun) light source, a single colored-glass-material mesh which you shape-key appropriately and a diffuse screen for the camera to watch and use it to render an entire movie!
It'd take approximately 'till the heat death of the universe to be noise-free but it'd be awesome nonetheless!
(Ok maybe not really)

[GemExtractor]

Do you know if it is possible to have retroreflective caustics?

[VincentOak]

there aught to be some sort of open source Programm to generate these.
unfortunately i have zero Programming skills

[robertoguerra]

Six years later… caustic renders in blender… and still no 3d printer that will print smooth transparent things… maybe polishing a resin 3d print