This post marks the release of version 1.0 of our polyline unwrap plugin. As described in the previous post, this tool helps you position polyline masks more accurately by obtaining lines of samples at intervals along the length of the polyline. Think of it like a ribbon of sample points tracking the polyline, which is then laid flat as a single image strip. It is used in-house to quickly visualize and correct deviations from the ideal edge across multiple frames. As an example, footage of a cigarette burning was masked and linked to the unwrap tool (see image on the right).

This example video shows a yucky little roto problem…  Time lapse footage of a shape variant object. The colors flicker like mad, the shape is doesn’t interpolate well with few keyframes, there’s nothing for a point tracker to grab onto…  It’s just the sort of thing you need to use a spline on.

Many of the datasets we deal with are similarly shape variant, and many are essentially time lapse, or at least shot with a very, very slow framerate. In this case, we look at how you can check (and tweak) your polyline over time without A) having to select the points and B) having to SEE your point.  The burning edge of the cigarette is flying across the screen, but we don’t have to pan along to follow it.  The Polyline Unwrapper keeps the “edge” in one place in the viewer.  This makes it easier to find the shape, true, but more importantly, it lets you observe irregularities instantly.  Using the Filmstripper, you can arrange multple frames in a row to check for drift or any “peaks and troughs”.

Here’s a second example of Eyeon’s Fusion courseware showing the “overlay samples” mode, where the unwrapped sample points are plotted over the original image.

Unwrapped example from Eyeon's courseware

Download PolyLine Unwrap 1.0
Download Example files

There’s some other fun stuff in the example comp, like using it on a paint stroke, instancing the result to another input, and viewing the results in a Trails tool.   Have fun, and experiment!

Footage courtesy openfootage.net