Local direction of travel (particle axis)

[Narad13]

I would do 2 things:

1) To align particle transforms to face normals, use a Rotation operator set to surface alignment mode and also disable 'affect particle shape orientation'. That will cause only the transform to rotate, allowing you to orient particle Z-axes to the surface.

2) Use the Position Transfer workflow to simulate the particles on a static deer, and then transfer to the moving deer after. It will make your life a lot easier There's an official example scene showing how to use that operator but it's pretty simple.

Yes this is perfect!!!
I was already doing tip #2 because you advised me of that earlier in this project.
But the Rotation-surface alignment is EXACTLY what I needed.

Thanks so much for always being around to provide support for this great product!!!
E