Niagara Spawning particles along a SubUV texture

I am looking for a way to spawn particles along a subUV texture to achieve an effect like a symbol being drawn by the particles. anybody know how?

You could try Sampling brightness, see this tutorial:

Or alternatiely, if you don’t want to sample GBuffer, you could render your flipbook/subUV material to a renderTarget. Then sample the renderTarget in Niagara, and read the brightness values there directly.