Discussion is over there > https://discuss.pixls.us/t/motion-blur- ... y/42841/15 (please give David Tschumperlé a lot of thumbs up)

Click on that roundabout arrow to update your G'MIC's filters (version 3.3.5 and up)


And you will have a NEW filter in "Degradations > Blur [Motion]" with up to 5 control points, yes you can zigzag the blur!

But even Better with the option "Mode >> Max (Slower)" ... you can have some effects that... >> speaking is not enough, a picture is worth thousands words

Looks like a possible cool way to create caustics, Pix; might give it a whirl if I ever get my spark back.