Looking to have particles slowly rotate as they move

#1

So I have a particle sim with instanced shaped balloons. They’re all rising slowly (using negative gravity) into the air.

They all need to be rotating slightly as they rise. All rotating independently on the Y axis (not rotating as a particle system like they would if I were to use a vortex field)

I’m not exactly certain how to implement this though. Can someone point me in the right direction. I’ve got “all data types” toggled and RotationPP turned on but I don’t know exactly the right way to connect it.

Thanks!!!

#2

I’ve made some headway. I’ve added these expressions to a user created “MyRotation” attribute:

nParticleShape1.MyRotation=<<rand(0,0),rand(0,360),rand(0,0)>>;

I’ve added these expressions to a user created “MySpeed” attribute:

nParticleShape1.customSpeed = rand(-10,10);

Then I’ve added this expression as a runtime before dynamics expression:

nParticleShape1.MyRotation += nParticleShape1.customSpeed ;

This is causing all of the particles to rotate at random. Great! Now I just need to figure out how to turn off the rotation on the X and Z axis and have it only rotating on the Y axis.

Any ideas?

#3

I haven’t tested, but I think the following will work:
myParticleShape1.MyRotation += <<0, nParticleShape1.customSpeed, 0>>;