Better control of particle rotation?

[HarryMcCurly]

Hey there,

I want the concave side of the particles to face towards the ends of each branch in 2.91.2:
Acropora Aspera.blend (1.0 MB)

No matter how I arrange the particle, or what orientation axis in the particle setting I set, I don’t get the results I desire.

Is there a way to have full control over the rotation of the particles and their orientation? Or is there maybe another way to arrange/align instances in a specific way? I’ve seen videos about complex arrays with curves along a mesh, but this is more useful for just one row or line.
Ive also tried multiple particle systems with different alignments, but the particles never do what I want them to.

Is it even possible with a particle system to align particles in a very specific way?

[LordoftheFleas]

Yeah I just found out that it IS possible, but probably a pain in the posterior to implement:

If you set the Orientation Axis in the particle system to Normal-Tangent, then the rotation is controlled by the UV-map of the emitter, meaning that if you align the UV map of your branches accordingly, you can control the rotation of the Polyps:

I)

II)