Hey, this one is easy, I know the answer. Sorry, too much hours working. The path mapper reorganizes data according to the output path you typed. In your case, the output its ONLY the path index. IF you want "0's" you have to type them into the output part of the path mapper.
{path_index;0;0}
{0;0;path_index;0}
or whatever you need. Thats the amazing capacities of PathMapper.
Hola Pep, thanxs for the quick answer. The problem I have here is that the empty branches change as the model changes, so I can´t type the branch index 'cause that empty branches are not always sorted the same way (in the jpg's case the branches are the zero,the first, the second and the third, but could be another ones as the model vary) So the problem is not I want to manipulate the index of the branches but to KEEP ALIVE the branches that have no items (as I show in the jpg, I don´t mind if the branches have 0`s or not)