I"m currently struggling with creating a grassy scene. I detailed an issue I'm having with scale in this question, but I'm also having an issue with rotation and direction which I'll ask here.

I would like the rotation of each blade to be randomized around the Z axis to give the grass less of a structured, "combed" look. I though the panel section labeled "Rotation" looked promising, but as soon I enabled it all the grass particles laid down parallel to the X axis. This despite the fact that the orientation axis is selected as "Global Z", which is straight up in my picture. I only get the desired effect if I set the axis to "Global X". I could just set it there and be done, but I prefer to know what I'm doing.

All transforms have been applied to the emitter and source objects.

Toggling "Object Rotation" only rotates the blade along its local Z axis 90 degrees, regardless of what the axis orientation is set to.

How do I get the blades to be oriented in the direction I want and rotate randomly along the blades Z axis?

Blades all aligned, no rotation

Blades oriented to global Z???

  • $\begingroup$ Rotations for hair particle objects can be a bit of a pain sometimes. You need to have a Phase value that is not 0 before the Randomize Phase will work, which both together produce random rotation. If you get to a point where your particles are oriented the wrong way (ie: on their side), select the particle object (the mesh you used to instance the particles from) and change it's orientation by selecting the whole thing in edit mode, and then rotating/moving it. If you also keep an eye on the particles on your emitter, you'll see how they "reorient" accordingly when you do. $\endgroup$ – Christopher Bennett Nov 22 '20 at 17:44

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