[robro1207]

Hi,
I'm trying to implement a wave deformation to a 3D cylinder. It's exactly the same as the DEFINE_GRID_MOTION example in the UDF manual, but in 3D. My UDF is giving me the negative cells found error. Any ideas about why my code isn't working?
My UDF:
/************************************************** *********************
udfexample.c
UDF for a node movement of a 2d rectangular pipe
************************************************** **********************/

#include "udf.h"

#define D 2e-6
#define l 630e-6
#define freq 1

DEFINE_GRID_MOTION(grid_both,domain,dt,time,dtime)
{
face_t f;
Thread *tf = DT_THREAD((Dynamic_Thread*)dt);
int n;
Node *v;
real radius;
real theta;
real x,y,z;



SET_DEFORMING_THREAD_FLAG(THREAD_T0(tf));
/*Set flag to induce that a current's node position has been updated only once */
begin_f_loop (f,tf) /*Loop of faces*/
{
f_node_loop(f,tf,n) /*Loop of nodes on every face*/
{
v= F_NODE(f,tf,n);
if (NODE_POS_NEED_UPDATE(v))
{
NODE_POS_UPDATED(v);
x = NODE_X(v);
y = NODE_Y(v);
z = NODE_Z(v);
radius = D/2.0*sin(x*M_PI/l*2)*sin(2*M_PI*freq*CURRENT_TIME);
theta = atan(NODE_Z(v)/NODE_Y(v));

NODE_Y(v) = radius * cos(theta);
NODE_Z(v) = radius * sin(theta);
if (NODE_Y(v) > (D/2.0))
{
NODE_Y(v)=D+y;
}
else
{
NODE_Y(v)=-y;
}
if (NODE_Z(v) > (D/2.0))
{
NODE_Z(v)=D+z;
}
else
{
NODE_Z(v)=-z;
}
Message("%lf %lf\n",x,y);

}
}
Update_Face_Metrics(f, tf);
}
end_f_loop(t,tf)
}

[AlexanderZ]

probably you have typo here

Thread *tf = DT_THREAD((Dynamic_Thread*)dt);

this is what you don't need (Dynamic_Thread*)

compile your code, read log.
didn't check for other problems