What causes caustics not appearing on the underwater floor?

There is no light source projecting the caustic pattern, so the seabed stays evenly lit with none of the rippling light an underwater scene needs.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Caustics Not Projecting Onto the Underwater Floor

Quick answer: Project an animated caustics texture downward via a cookie on a directional light, a projector, or a decal, masked to submerged surfaces and tinted by the water.

The floor beneath the water is flatly lit with no shimmering light patterns. Caustics are not automatic; you must project an animated pattern onto the surfaces under the water.

How to fix it

1. Project the pattern

Use a flipbook or scrolling caustics texture as a light cookie on the sun, a decal, or a projector aimed down so the rippling pattern lands on submerged geometry.

2. Animate and break up tiling

Cross-fade two caustic samples at different scales and scroll speeds (a dual-layer blend) so the pattern animates without an obvious repeating grid on large floors.

3. Mask to underwater only

Restrict caustics to surfaces below the water height (via depth or a volume) and tint them with the water color and intensity so the effect stops cleanly at the shoreline.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unity error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.