Here is an example of a possible wind force I made a quick movie in Flash, a black odd-shaped oval (might lend to having soft edges...) moving across the movie screen, saved it as quicktime movie. In Carrara, used AnythingGrows - took way too long to figure it out : ( but did, I think. In Carrara, add a plane, add AG on plane, add the movie as a Color shader to the plane - hide the plane, in AG settings, at the beginning of your animation make sure the settings don't change from beginining to end, else all the grass will move. Set the x and y wiggles to the shader containing the movie in color channel. Make sure to key frame the beginning of the movie shader - start at start, and advance the little preview movie to the end at the end of the animation. Also... there must be bend in the grass... play around with it. It took me the better part of 2 hours to get it to work, and I even got one to work, then 1 hour later, figured out how I did it. The link is to a test render. I imagine you could use any kind of movie - waves, some moving contrasting color, etc. to create movement in the wiggle.

Never Give Up!