Fully customizable ventilation grill

!!! Don't forget to like it if you like it !!!!

### Note: if you are not satisfied with rectangular or round ventilation grids, have a look at my newest Design: https://www.thingiverse.com/thing:6955016
###

This Thing is a fully customizable ventilation grill that allows you to construct a wide range of ventilation outlets just by changing some parameters.
This is a remix of Thing: https://www.thingiverse.com/thing:3320712
It introduces some new features like:
* Possibility to make slanted ribs
* Sizing now based on the required cut out
* The ventilation ribs are now automatically centered by default, but can also be shifted by providing an offset.
* The shape of the brim can be independently set from the tube - different radiuses are possible.
* Quicker calculation due to re-writing almost the complete code.

An updated file has been uploaded with the ability to rotate the grid within the frame.
Also the creation of round grills is now much easier - you just need to set the tube r