You don't need to do it in a precomp anymore if you're using a newer version of After Effects. You can simply point the Displacement Map effect at the layer with the Fractal effects, blurs, etc. and tell the Displacement map to use the layer with effects and masks and not just the layer source (it's the second dropdown to the right of the layer picking dropdown).
It makes it easier/faster to iterate on things since you don't have to keep diving into and out of precomps.
- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')
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