Caustic (optics)

The word caustic, in fact, comes from the Greek καυστός, burnt, via the Latin causticus, burning.

In ideal circumstances (including perfectly parallel rays, as if from a point source at infinity), a nephroid-shaped patch of light can be produced.

Some computer graphic systems work by "forward ray tracing" wherein photons are modeled as coming from a light source and bouncing around the environment according to rules.

Caustics are formed in the regions where sufficient photons strike a surface causing it to be brighter than the average area in the scene.

“Backward ray tracing” works in the reverse manner beginning at the surface and determining if there is a direct path to the light source.

This is especially true when it comes to real-time graphics in computer games[8] where generic pre-calculated textures are mostly used instead of physically correct calculations.

To tackle this problem, optimal-transport-based is one of the existing proposed methods to control caustic pattern by redirecting light's directions as it propagates through the surface of a certain transparent material.

Once the caustic pattern has been designed computationally, the processed data will be then sent to the manufacturing stage to get the final product.