caustic-glass
The shot read through a window that won’t hold still. Light pooling at the bottom of a swimming pool. The world behind old hand-poured glass, warm and unreliable.
demo.cinerune project.
What it’s for
Light remembers water. The bright ribbons that crawl across a
pool floor at noon, the smear of a streetlight through a
rain-run windscreen, the soft lie of a 1970s shower door —
caustic-glass puts the ASCII behind all of it. A
domain-warped fbm field bends the frame the way thick uneven
glass actually bends it, never evenly, never the same twice,
and across the bright parts only it lays caustics: those
flickering threads of focused light that pool and slide.
Because the caustics ride a brightness threshold, dark scene stays dark and undisturbed while highlights catch fire and move. That asymmetry is what reads as glass rather than as a wobble — the eye trusts the shadows and watches the lights dance. It carries dream sequences, underwater POV, a memory that won’t resolve, a title card seen through a held tumbler.
Reach for this when: a scene needs to feel submerged or
half-remembered rather than sharp — lift warpAmount
and flowSpeed together for water in motion, or keep
the warp low and let only the caustics shimmer for sun through
a slow window.
Where it lives in the app
Effect group Optical & lens in the effects tray. It runs as a full-frame pass and can be gated by a mask layer — fog the glass over one corner of the shot while the rest stays flat behind clear air.
Parameters
| Key | Range | Default | Effect |
|---|---|---|---|
warpAmount | 0–1 | 0.5 | Strength of the refractive distortion |
causticScale | 0.5–12 | 4 | Size of the caustic light pattern |
flowSpeed | 0–2 | 0.6 | How fast the glass flows |
highlightThreshold | 0–1 | 0.55 | Brightness above which caustics appear |
dispersion | 0–1 | 0.2 | Chromatic spread at the refraction |
softness | 0–1 | 0.4 | Edge softness of the warp |
Pairs well with
- bloom — let the caustic threads blow out and bleed. The light stops being a pattern and becomes something that hurts a little to look at.
- palette quantize (cyan) — push the whole thing toward chlorine blue and it’s unmistakably underwater. The warp does the rest.
- chromatic aberration — stack a real lens fringe on top of the dispersion and the glass gains thickness, like you’re looking through the bottom of a bottle.
- slow zoom — drift the frame in while the glass flows the other way. The shot breathes; nothing sits still long enough to be sure of.
Demo project
The downloadable demo.cinerune
is this single effect applied to Cinerune’s bundled
code-assembly plate — an amber procedural portrait — with
caustic-glass over it. Drop it into the editor
(File → Open from disk…) to tweak parameters live. The
frame shown above is exported from the same project.