Surely a Bug!

A free "Happy Accident" generative shader — an abstract animated pattern born from a bug that looked too good to fix. Originally by Mrange, adapted for your host, with lots of parameters to make it your own.

Quick Start

1. Apply the effect to a clip.
2. Browse the presets — each one is practically a different effect.
3. Tweak parameters freely; there are no wrong answers here.

Extra Inputs, Mattes & Alpha

Applies to AVFX effects updated August 2026 or later - you'll know your build has it if you see the "Alpha/Matte" parameter group.

This section is shared by the documentation of every AVFX effect - the information here is general, not specific to this effect.

The short version

The AVFX effects framework supports any number of extra inputs in addition to the clip the effect is applied to - for example: a blur map, a custom bokeh shape, an external matte, and so on. In most hosts, each one simply gets its own connection: After Effects and Premiere Pro give every input its own layer selector in the Effect Controls, and in Fusion (and other node-based hosts) each node gets a "port" for each input, as you'd expect.

Alpha is the fourth channel of the image itself - the "A" in RGBA - used for compositing downstream of the effect. It rides along with the RGB through the processing, and embedded alpha behaves just as you'd expect: if your source clip already carries an alpha channel, nothing special is needed.

The one ability AVFX adds everywhere: your input alpha can come from the source's embedded alpha, or from an external matte injected in its place. A matte is any grayscale or RGB clip - its brightness becomes the alpha (the matte clip's own alpha channel is ignored, so it doesn't need one). Unlike other extra inputs, which steer how the effect processes the image, the Matte input feeds this alpha. From there it rides through the processing along with the source's RGB, just like embedded alpha would, and what emerges is the output's alpha - consistent with the processed image, because it went through the same processing.

The Alpha Source selector (in the Alpha/Matte group) chooses where the input alpha comes from: Auto (the effect picks sensibly), Source's Embedded Alpha, Matte Input's Luminance (called Matte Layer's Luminance in After Effects and Premiere), or Opaque (Alpha = 1) - the escape hatch when you just want a solid frame.

Premultiply Output depends on what the effect hands you, so there is no single right setting:

• Turn it ON when the output is a processed picture carrying a matte in its alpha - the usual case when you feed a Matte input. Without it, Resolve's timeline composite leaves bright fringes or sparkle along the matte edges.
• Leave it OFF when the output is an element on black, such as Optics Reborn's "/ Alpha" glow modes. Those already have their coverage baked into the color, so switching it on multiplies it in a second time and gives you a dark edge instead.

Rule of thumb: ON if the frame still looks like your shot, OFF if it looks like a glow floating on black.

One host is different: Resolve's color page handles inputs and alpha in its own way, and is described in the next section. If you don't use the color page, skip straight to your host's section below.

Resolve color page

A color-page node accepts at most two connections. The first is always the main image being processed - so every extra input the effect can accept has to share the second connection, and that second input can only serve one function at a time. This is a limitation of Resolve's color page.

That's what the "Resolve Color Page: Input 2 Routing" group is for: choosing which of the effect's extra inputs the second connection serves - a map that steers the processing, or the Matte that feeds the alpha. Take Advanced Lens Blur: there are three possible uses for its second input - the Kernel (an image used as the bokeh shape), the Blur Map (brightness controls blur strength per pixel), or the Matte Input (external alpha for compositing). You can only use one of these at a time, and the "Use Input 2 As" selector is how you choose: connect your clip to the node's second green input, then set the selector to the input it should feed. (The Matte Input is always one of the choices - the framework provides it on every effect. If an effect has no other extra inputs, there's no selector at all: the second input simply is the Matte.)

If you need two of them at once - say, an external matte and a custom kernel - you'll have to use the Fusion page (or another host), where all of the inputs are available simultaneously.

Don't rely on embedded alpha on the color page - its results there are unpredictable (the color page does some things under the hood that are out of reach of the OFX plugin). Feed a matte through Input 2 instead (Use Input 2 As → Matte Input).

Compositing: in Resolve, the color page and the timeline share the job: the actual comp happens on the timeline - your clip sits on a video track above whatever it composites over - while the color page is where the alpha is produced. The timeline only sees that alpha if you explicitly export it from the node graph: right-click in the color page's node area, choose Add Alpha Output, and connect your node's blue alpha output to it. The effect's node already carries the alpha - "OFX Alpha" is enabled by default - but you should also right-click the node and deselect "Use OFX Alpha for Mixing": that setting turns the alpha into a mix mask between the node's input and output instead of compositing coverage, which is almost never what you want.

Resolve/Color Page Troubleshooting:

• Bright fringes or "sparkle" at matte edges during playback - turn ON Premultiply Output. If you followed the Compositing steps above, "Use OFX Alpha for Mixing" is already off, so that is not the switch that helps here - Premultiply is. (Stills can look clean while motion sparkles: playback renders at reduced resolution, which creates the fractional alpha that exposes the mismatch.)
• The composite looks like a blend of the clean and processed image at the edges - same cause: "Use OFX Alpha for Mixing" is ON. Turn it off. (If the whole frame looks blended with the source, that's a different knob - check that Global Blend is set correctly.)

After Effects & Premiere Pro

Each of the effect's inputs has its own layer selector in the Effect Controls - pick any layer in your comp (or Premiere sequence) for each one. It's best to precompose vector layers (shapes, text) before using them as inputs.

Compositing: for glow or element outputs, set the layer blend mode to Luminescent Premul - the Normal mode attenuates premultiplied elements twice and leaves a subtle dark edge. Keep Blend at 1 when compositing with the effect's alpha (Blend mixes the untouched source back in, alpha included) - fade with layer opacity downstream instead.

AE Troubleshooting:

• Dark edge on glows - the layer blend mode is Normal; switch to Luminescent Premul. If it's darker still, Premultiply Output is ON; turn it off.

Fusion & everywhere else

Fusion (and Resolve's Fusion page) gives the node a connection per input, and compositing needs no special setup: the effect's output carries its alpha embedded, just as you'd expect, so wire it into an ordinary Merge node and leave its settings at their defaults.

General Troubleshooting:

• If the same comp looks different in different hosts - the math is identical in every host, but the color transforms might not be. Make sure you're evaluating everything through the same color pipeline. (In Resolve, that means pinning the project's Timeline and Output color space to your delivery standard before comparing.)