REAL PHOTON CAUSTICS ARE FINALLY HERE.

ONE CLICK. REAL CAUSTICS.

SO FAST IT FEELS FAKE.

Real time, right in your viewport.

ONE CHECKBOX.
FOUR KINDS OF LIGHT.

IT REALLY IS JUST A CLICK.

Open a scene. Tick one box.

An ordinary scene, opened as it was saved. Nothing in it was prepared for this — no special materials, no extra lights, no node setup. Watch the bottom right of the panel: the caustics are in the render before the mouse has moved away.

Then move your light.

The light is moved in the viewport on the right, the render on the left keeps up. No re-render to check, no pre-pass, no cache to rebuild — you just drag until the shot looks the way you want it.

THE WHOLE SCENE, OR
ONLY WHAT YOU PICK.

By default every material that can bend light casts caustics, and you never think about it. In a heavy scene — an interior, a full set — switch Casters to Selected Materials Only and tick just the objects that matter. Everything else still catches caustics, it simply stops sending them, and the entire photon budget goes to your hero.

BEAUTIFUL, PHYSICALLY CORRECT CAUSTICS —
NOT A DREAM ANYMORE.

Progressive photon mapping — the same class of solver Corona uses for its caustics, but traced on your GPU instead of your CPU. Physically correct, not an approximation.

THE SAME BOTTLE INSIDE BLENDER

SAME SCENE. SAME MATERIALS.
SAME LIGHTING.

Just one checkbox ticked. No setup at all.

INDEPENDENT REVIEW

DON'T TAKE OUR WORD FOR IT. TAKE HIS.

“It's actually game changing.”

OWEN JENKINS  ·  3D ARTIST  ·  YOUTUBE

Owen got a copy, spent a weekend rendering his own scenes with it and made a 15 minute video about what he found. Unscripted, in his words.

IT WORKS ON EVERYTHING YOU MAKE.

ANOTHER BOTTLE, ANOTHER LIGHT SETUP

PRODUCT VISUALISATION

THE SAME VASE.
TIMED BOTH WAYS.

Same scene, same lighting, same glass. One render without the solver, one with it.

CAUSTICS AREN'T A DETAIL.
THEY'RE THE LIGHT.

One side is Cycles doing everything it can. The other is the same file with the solver switched on — nothing else touched. What comes back is not a highlight on the glass. It is most of what you see.

WORKS WITH EVERY MATERIAL.

Glass, metal, car paint, your own node groups — the solver reads them all.

All your scenes and materials just work. No setup — only the Photon Caustics Solver checkbox.

BIG SCENES. SAME CHECKBOX.

Windscreens and chrome light up the whole set — and the checkbox is the only thing that changed.

MORE LIGHT. SAME CHECKBOX.

Ice in a drink. Beams in the fog. Rainbows from a diamond. And Blender’s Path Guiding on your GPU. A free update for everyone who owns Caustica.

ICE IN WHISKY.
FINALLY RIGHT.

Plain Cycles treats every glass, liquid and ice cube as if it sat in air. Ice turns into bright glass blocks, and the glass gets a second wall where the liquid touches it. With nested dielectrics, light goes from glass into whisky into ice with the right refraction at every boundary. The ice almost disappears in the drink, just like it does in a real glass, and the caustic on the table follows.

LIGHT YOU CAN SEE
IN THE AIR.

Caustics no longer stop at the floor. Light bounced off car paint or bent by waves draws visible beams through fog, haze and water. In plain Cycles, that light never reaches the fog. One more checkbox: Volumetric Caustics.

WHITE LIGHT IN.
RAINBOWS OUT.

Blender 5.3 lets glass split light into its colours. Caustica makes the caustics follow: every prism, diamond and glass edge throws a real spectrum onto the surface. Set Dispersion on the Principled BSDF and that’s it.

STUDIO GALLERY

ONE SUN. ONE PIECE OF GLASS.

PATH GUIDING.
NOW ON YOUR GPU.

Blender’s Path Guiding has only ever run on the CPU. Caustica brings it to CUDA and OptiX, with nearly identical results to Blender’s native CPU Path Guiding and 22× more samples in the same time.

It helps where light reaches the camera only indirectly, through doors, gaps and small openings. Off by default, under Render ▸ Sampling ▸ GPU Path Guiding (experimental).

PHYSICALLY CORRECT.
THEN YOURS.

One slider takes the caustics up or down. 1.0 is the physically correct answer — everything above and below it is a look, and the render updates while you drag.

Only the hero should throw light? Switch casters to selected materials and tick the ones you mean. Everything else still catches caustics — it just stops sending them.

PULL THE CAUSTICS OUT.
LIGHT BY LIGHT.

The caustics arrive as their own render pass. Add light groups and you get one caustics pass per light — so you rebalance the lighting in comp instead of rendering the shot again.

NO SECOND
RENDER ENGINE.

Until now, real caustics meant leaving Cycles: rebuild the scene in V‑Ray, Corona or LuxCore, render a caustics pass there, comp it back over your Cycles render. Different materials, different lights, different look — for one effect.

Nothing to install. Nothing to export. One render, one engine, one pass.

IT IS BLENDER.
PLUS ONE CHECKBOX.

Caustica is a custom build of Blender 5.2 and Blender 5.3 — 100 % the official Blender source code, with one function added. Caustics have to be traced inside the render kernel, so they cannot come as an add‑on.

The only thing that changes: you download your next Blender here instead of blender.org.

NOTHING TO
INSTALL.

Caustica is a complete Blender build, not an add‑on. It sits next to the Blender you already have — it does not replace it, and it does not touch your installation.

ZIP TO FIRST CAUSTICS: TWO MINUTES.

Unedited, start to finish — open the folder, launch Blender, build a scene, tick the box, watch the caustics land. Sped up for you; the whole thing took about two minutes in real time.

[email protected]

Written by one person, answered by the same person.