[mrestrepo30]

Hi,
I'm calculating the displacement of the nodes by comparing two grids at different times, so the way it does it, is that it goes through the faces of a thread, and then on each face goes through all the nodes. However, as some faces "share" nodes, I end up calculating the displacement for one node several times.

I tried to use something I found in the GRID_MOTION macro:

f_node_loop (f1, t1, n1) {
node1 = F_NODE(f1, t1, n1);
if (NODE_POS_NEED_UPDATE (node1))
{
NODE_POS_UPDATED (node1);
......

However when I use this the UDF never goes inside the IF, so I get no information from the nodes. Does anyone know how to implement this function on a ON_DEMAND macro?

I appreciate any comments about it!