I did a little observation of my yard today and I found out some interesting
things about grass movement.
    First, only the longer blades bend very much, and when they do, it is really
a complex sort of movement.
    Second, the movement has two distinct components- bending and oscillating.
When the wind blows over longer stalks or leaves, they tend to bend gently over
the length, pretty much as the parabolic bending in your model.  It may actually
be a catenary curve due to the forces and loading, but that is a small thing.
    But the oscillating movement is a side to side twisting, more rapid for
shorter blades than for longer ones.  The oscillation period is much shorter
than the bending or waving period.  The wind moves in "swells" over large,
curved or crescent shaped areas, exciting the stiffer stalks to oscillate more
and the thinner or longer ones to bend and curve.
    This is way too much complexity I think for the model you have.  The texture
itself looks great as it stand; getting realistic looking movement may be far
harder than it is worth right now.
    If I were modelling grass and leaves in the wind, I would attach masses or
springiness to control points and apply forces against them.  Otherwise, the
movement tends to look more like seaweed drifting in the water, which is
essentially what your texture may naturally tend to emulate.  Don't give up; it
already makes nice turtle grass for undersea animations!

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip

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