Cannot aim particle system

I'm asking how to set the shape.rotation on a ParticleSystem in 2D. I've tried setting the z value directly a few ways and then tried the rotation.Set method to no avail (directly and also from a variable as in the example below).

It would seem that this should be straightforward. If I change the shape.rotation in the editor it works as expected. I just can't get the rotation change to "stick" in code.

Class Level Fields

public SpriteRenderer renderer;
private SpriteRenderer parentRenderer;
private ParticleSystem particles;

void Start() Initialization Code

List<SpriteRenderer> spriteRenderers = GetComponents<SpriteRenderer>().ToList();
renderer = spriteRenderers.Where(b => b.name == this.name).FirstOrDefault(); // there is only one and it resolves correctly
particles = renderer.GetComponent<ParticleSystem>();

Attempting to set the shape.rotation on the particles in FixedUpdate():

// determine angle, adjust for negative values
var p1 = particles.transform.position;
var p2 = PlayerCharacter.PlayerInstance.transform.position;

float angleToPlayer = Mathf.Atan2(p2.y - p1.y, p2.x - p1.x) * 180 / Mathf.PI;
angleToPlayer = angleToPlayer > 0 ? angleToPlayer : angleToPlayer + 360f;

var shape = particles.shape;
shape.rotation.Set(0, 0, angleToPlayer);

var test = particles.shape.rotation; // always 0,0,0 - expecting Z value to be set to the value of angleToPlayer

particles.Emit(1);

I will heap praises upon whoever can answer this. Took long enough to get the angle stuff working correctly (there's a Raycast2D that works but is not in the code example). I have a lot of C# experience, but Unity doesn't always function as I would expect.

Thanks,
turp182

 

More info. Here's a screen shot where I have pinned the shape.rotation value (0,0,45 - default value on the prefab). It also shows the angleToPlayer at 267 degrees. Finally, the execution point (yellow line) is past the shape.rotation.Set(...) call.



Here's some of the particle settings (in flux, focusing on scripting first):

 

I figured it out, I had to create a variable for the Vector3 rotation, now it works:

I can't figure out why there is a shape.rotation.Set method...

Vector3 rotationVector = particles.shape.rotation;
rotationVector.z = angleToPlayer;
shape.rotation = rotationVector;