I’ve already linked through the product of this directly to the project board, but it might cross of an LO, even if partially, so here it is again.
Took me the better part of the night to get it the way I wanted, but in the end the effect is easily transferable and extendable to another file.
The tutorial used to create it can be found below (I recommend muting the music, unless you’re into it).
Not great quality on the resolution there, which honestly made it far more difficult to follow than I would have liked, and the author has a bad habit of jumping his mouse all over the place, so I’ll summarise the process.
The effect itself is a turbulent noise filter with the fractal type set to ‘string’, tilted to a semi-horizontal angle over the sky of the scene and scaled up. To achieve the aurora effect the noise then needs to have the CCLightburst effect applied to it with a negative setting on ‘ray length’ and the burst set to ‘fade’ will give the blanket of light that the northern lights create.
To make the light move change the ‘evolution’ value on CCLightburst as time passes in the scene. The colours are a tint applied over the noise layer. To add more colours I just duplicated the layer with a different colour applied to the tint, as well as changing the values for ‘ray length’ and ‘burst’. In particular to get the outline at the bottom of the aurora the ray length on one layer should be set almost to zero. To achieve a more pronounced variance in the colour graduation there should also be a levels effect applied so as you can adjust the black and white settings. With all the aurora layers set to ‘add’ mode this will graduate the transparencies.
Evidence would suggest a few fellow students already know the effect, but hopefully this will be useful to someone else on the project. I enjoyed learning it anyway.