### Perform while loop

The While control node allows you to execute a subpart of the composition as long as a given condition is fullfilled. The condition is tested before the first step is executed.

The node layout has two blocks:

- The top one enables to define the loop criterion. The bottom block is executed if only this criterion is valid.
- The bottom block is actually the body of the while loop. It contains the subcomposition that is executed when the top criterion is valid.