function nodes2 = maskFEM(nodes,vel)

a = [];
b = [];
c = [];
ind = 1;

for i=1:length(nodes)
if vel(i)>0
    a(ind) = nodes(i,1);
    b(ind) = nodes(i,2);
    c(ind) = nodes(i,3);
    ind    = ind +1;
end
end

nodes2 = [a', b', c'];