I have some simple cutout particles of leaves that are set to collide only with the terrain. Once they collide I have dampen set to 1 but they continue to rotate in place on the terrain. Any idea what setting I need to change to prevent them from rotating? Here is a copy of my settings (thanks in advance!):
I know this is late but you can use rotation by speed with curves because when it lays on the ground it should have speed 0
I found a solution,
1.Check “Rotation by Speed”
2.Set Angular Velocity (Under Rotation by Speed) to “Random Between Two Curves”
3.Set the curves as shown in the picture:
Explanation of the curve: Each curve has 0 value until a threshold, as soon as the threshold value is reached the angular velocity is made maximum i.e 900 in my case.
The threshold value (Horizontal Axis Value) will be different for different “start speeds”,my start speed is 9 hence the curve.
adjust the curve farther away from 0 on horizontal axis to get better results!
Hey guys, so i’ve nailed down how to stop rotating particles upon collision using sub Emitters, here’s the settings to do so.
The theory is- Fire particles which rotate with speed, when they collide with the world, they die; which in turn triggers a kill command removing the particles from the scene.
when the particles die, the Sub Emitter spawns new ones which matches the rotation of the main emitter. By turning off a shape emission, they match the old translation.
hope this helps, made my brain fuzzy for a bit.
Graham
Hi mostlyhuman,
Did you find the solution to the problem you had with the rotation of the particles after collision?
I’m having the same issue here.
I have not 
be sure and post back if you do figure it out !