Grass that reacts to forces (and force generation)

Hi all

I did search for this but I found no answers that satisfied my question. I’ve played the game Flower on the PS3, and loved the waving grass, and how the wind dynamically blows it around- but is this possible in the BGE? Alpha maps seem OK, but I struggle to imagine a way that allows for dynamic movement when colided with (either by an object or by a force).

I was thinking of having a plane animated with an IPO (that plays on collision), but how could this be orientated towards the source of force? And more importantly, could things like wind be generated? A linear X force would be OK, but what about a vortex?

Any thoughts? Cheers for your time!


You could use a shapekey, perhaps in conjunction with an armature to point the grass blade, though that many bones would kill the framerate. Perhaps you could use a single shapekey to control the bending, use the force amount to control how much bending occurs, and then orient the blade towards the force direction.

Thanks, I had thought about a shapekey. The other thing I was thinking to use was a 6 DOF constraint (if I could get it working!), although that would only be suitable for large bushes, not 1000 plus blades of grass.