Salut Gérald, Merci pour ta réponse détaillée et ta disponibilité... < French people inside ;)

I don't know if you use a version with a checkbox named "Springs CPU".

I have a "Sticks CPU" checkbox, it is checked by default, is it the option you are refering to ?

I think you use Ctrl-Alt-Del keys to stop the process.

No, never :)

Personally, I always use Ctrl-Shift-Esc. These keys have two advantages:

Yes, I prefer to use this key combination too ;)

they allows to show the program manager in all situations, The issue is that if you have the Scene Viewer on, it is opened in a "always on top" fashion, you cannot bring the task manager in front of it. You need to drag the window to a side of the screen to see the windows below. But that is not possible when you are "stuck" in a simulation that takes forever (too many springs or any other reason)

Thanks, can't wait to see the final V2. Good job on this software !