How to remove children rotation? I have a grass particle system on an open field and the grass is animated to look like it's swaying in the wind. So I want the grass to face the same direction, but when I try to use children (both simple or interpolated) they suddenly face different directions. I've tried turning off rotation and set every setting on the children settings to zero, but they still have random rotations. Is there a way to fix this, or should I resort to putting hair number to 100,000? 

So basically, I made a model of three low poly blades of grass, put some armature on them and animated them to make it look like they were being blown by a bit of wind. If I put it on a plane or landscape with no rotation whatsoever, it looks perfectly fine and is similar to the results I wanted, but when I use children, the grass suddenly turn in random rotations. 

Here's what it looks like when I put it on high numbers with no children. 



and here's what it looks like with low numbers (1000 on this image) but with children. 


My PC can't handle physics very well, but if there's no solution then I guess I have no choice.
Set parting option to 1: 



Default zero parting used to interpolate children strands between nearest control strands, that smooth transition from one control strand to outers (if you render hair, not objects).