Hi Talougo, welcome to the forum and I'm glad that you are having fun with MoI!

> One question : how could i do to bevelled a little bit more just the angles ?

Do you mean you want to apply a new bevel to the sharp corners on the red cutout areas? Or that you want to change the beveling that is already applied on to the outer edges of the cube?

For the first one you can select all the red faces by going to the scene browser and clicking the text "Rouge" under the Styles section, and then run the Fillet command to put a rounded edge on those - it will be limited to a pretty small radius value because there isn't much space available in some areas like here for example:



The fillet will need to be small enough in radius to fit within that space there.


For the second kind - editing the fillet that has already been applied to the outer edges - that's not quite so easy to do in MoI currently. That kind of deeper history editing is something that I want to make easier in the future (like being able to edit the radius and have the fillets recalculate). But for now it is easiest if you go back to some previous saved version of the model before you applied the fillets and then apply the fillet to them again. If you don't have a previous version, it is possible to remove the current fillets by deleting them and then doing an "untrim" of the faces to restore them.

There is a tutorial on that kind of delete and untrim mechanism here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17

In your case here what you would do would be to first delete the fillets, leaving empty areas like this:



Then select the edges around the outer boundaries like this:



And then push Delete to remove that trimming boundary and recover the full underlying surface there - that will restore those planes to their original size:



After you have done that to all the pieces you can then select the pieces and use Edit > Join to join them all back together into a solid with sharp edges and then refillet them.

There is also a script that you can set up for selecting "naked" edges (edges that belong to only 1 surface instead of joined between 2 surfaces), which can help with selecting the edges in this case, to set up that script you can add in a shortcut key and put in the script shown here:
http://kyticka.webzdarma.cz/3d/moi/#SelectNaked

That way you can select all those edges to delete with just one shortcut key press.

Hope this helps!

- Michael