I have been struggling for the rebuilding effect for a long time, just try to rebuild the fragments, file attached ,the setprimintrinsic doesn't behave as expected.

vector4 q1,q2;
matrix3 m;
if (@Frame==1)
{
matrix3 intM = primintrinsic(0,'transform',@ptnum);
q1 = quaternion(intM);//store original rotaion
}
if (@Frame==chi(“startFrame”))
{
m = primintrinsic(0,'transform',@ptnum);
q2 = quaternion(m);//store the rotation at start frame

s@collisionignore = “sphere_object1”; //disable collision so that fragments can return to original position
}
if (@Frame>chi(“startFrame”))
{
@force = 100*(@rest-@P);
vector4 q = slerp(q2,q1,fit(@SimFrame,chi(“startFrame”),chi(“endFrame”),0,1.0));//using fit
//vector4 q = slerp(q2,q1,ch(“completion”));//try directly using float
//vector4 q = slerp(q2,q1,0.01);//constant
vector r = cracktransform(0,0,1,0,qconvert(q));
m = matrix3(maketransform(0,0,@P,r,{1,1,1}));
//m = qconvert(q);//try convert q to matrix3 directly

setprimintrinsic(0,“transform”,@ptnum,m);//this doesn't behave as expected…
}