Sand Grain Interaction Help Needed

[Ramteen]

Hey folks, Hope all is well.

Working on a close-up shot, Where a snake penetrates through some sand. I like to achieve a gentle and realistic interaction between the two objects, Effects of sand rolling on the snake and each other is desired too of course. However I'm clueless of how this possibly could be achieved. 

Please check the attached scene below. , Any help or hint would be greatly appreciated. 

 

grain_init.hipnc

Edited April 4, 2018 by Ramteen

[John Svensson]

You can solve the rotation of the grains with a PointWrangle in a separate SopSolver

float dist = distance( @P, v@P_last );
v@P_last = @P;

vector axis = cross( {0, 1, 0}, normalize(v@v));

vector4 rotate = quaternion( dist / f@pscale, axis );

p@orient = qmultiply( p@orient, rotate );

Maybe one step closer to what you're after