If you are doing Matchmove, you probably bumped into Lens work-flow issue, where you have to un-distort the footage in your matchmove software, then track it, and export a new undistorted footage, so your client can compose the 3d rendering on top of it and then distort it back.
I don’t really like this work-flow, since for instance AfterFx do not have Cubic Lens Distortion FX and it would be really hard for the client trying to match the distortion back.
Thanks to Jerzy Drozda Jr (aka Maltaannon) for his great tips about Pixel Bender.
So now, you can create a new comp with your distorted footage > pre-comp it > undistorted it with the shader > track it in syntheyes > export the camera to a 3d package > render the scene > import the render into your pre-comp > desactivate the shader. Should match perfectly 🙂
(yeah I know, PFTrack grid with Syntheyes … not cool ! :p )
Cubic Lens Distortion (or undistortion as well) is well known in compositing or any VFX package. Basic Lens Distortion would usually solve the distord plate a the center, but closer you would get to the border of the picture, more the distortion will still there. The Cubic parameter let you control that.
It could also be used to give a “Chromatic Aberration” effect
This shader is based on the Algorithm shared by ssonTech website. This algorithm is used in SynthEyes (matchmove software) and is pretty simple.