Composite wrapping

I was wondering if anyone knew a simple straight forward way of getting an image to wrap around on the render edges when translated in the compositor (eg. pixels leaving the render area on the right reappear on the left edge)?

I’ve done this before by feeding two or more copies of the frame into different translate nodes, and mixing them, I was just wondering if there was an easier/more versatile way of doing it.


As I now I don’t think so, but an edgewrap/mirroring node would be useful - as an example we use that all the time in AE for camera shake, instead of scaling…

There’s a lot of useful nodes ‘missing’ in the compositor, but I bet there be quite a few more after Mango as they will run into issues compositing live plates - the compositor as it stands today is more suitable for in-Blender-use than with footage…


I’d come to the same conclusion, more or less. What I wanted to do in this instance is have a single frame constantly scroll vertically, to mimic bad TV reception, but be able to do it just by constantly incrementing the input value. I think I’ve worked out a hack that’ll do it though:

Take the input value and round it to the frame height, and subtract the rounded value from the input to get the frame offset. Pipe that into three separate translates and recombine to get a frame above and a frame below, offset so it appears the single frame is wrapping at the edges.

My quick test looks like this:

It’s not going to win any prizes for elegance, but it works and will make my life a little easier.

Hehe, it’s like with Nuke artists, they always say working with nodes are much easier to get an overview on what’s happening - yeah right, hehe… I often confuse the hell out of myself working with nodes… ;D

But a mirroring node is one of the basic ones in compositing so hopefully they’ll miss it and make one soon enough. Same thing about comp size/settings, also something lacking in the compositor… Perhaps time to start a missing nodes thread just in regard to the compositor… :slight_smile:

Mirror as in the Distort>Flip node? :eyebrowlift:

Citizen, I was going to post a nodegroup but instead found a bug — you can’t edit drivers within nodegroups. Going to have to look into this first.

I think I’ve come across that, I’ve usually ended up wiring anything changeable up with inputs.

Hehe, no, I of course meant a node for extending a plate through mirroring it on the sides, top- & bottom - like the ‘Motion Tile’ filter in AE or ‘Tile Repeat’ in Nuke… :slight_smile:

Edit: A function like that also needs a defined workspace, so without that there’s a lot that is tedious to do with the compositor as it stands today… Hopefully compositing live footage in Mango will show that need pretty quickly…

If you add you image as a texture it can be tiled/repeated via the offset.

Ha! Thanks neon! Would still need the math to map values, but is much better than the translate/mix combination.

Ha! Thanks N3on, would still need some math as offset doesn’t go on infinitely, but is much simpler and more versatile. :slight_smile:

What kind of “definition” are you looking for? There are ways of defining an image area used by the Compositor that is not limited to the Dimensions parameter in the Render context.

For the kind of scrolling described, the Translate compositor node isn’t always versatile enough in that sub-pixel increments are difficult to implement. For some flat-art effects it’s often better to use a second Scene with an ortho camera aimed at textured flat planes, a kind of virtual rostrum camera. This can be input into the Compositor via the Render Layers node.